Some call them crazy. But for people who believe they have seen UFOs, it is a very real experience.

So many times Suzanne Hansen will go back to the moment which occurred 29 years ago. If only she could just once fill in the gaps in her memory of a bizarre and frightening night in 1978.

Fridays were always a long day, the opportunity for Hansen, 23, and her husband to stock up in Gisborne for the week ahead, before returning to their isolated home on East Cape where she taught at the local school. On this occasion, after they shopped they had dinner with friends and didn't get on the road until 10.30. They had an almost three-hour drive ahead of them.

About 11.30 they reached an isolated point high up in the hills between Tologa Bay and Tokomaru Bay, and saw something they would never really speak about to each other again.

Hansen knows how many people react to her story. She's seen it in their faces for years. UFOs - the word conjures up images of skinny creatures with big heads. The alleged cover-up of a UFO crash in Roswell, New Mexico, the films ET and Close Encounters of the Third Kind, bizarre tales of alien abductions that have been tabloid fodder for years. Always good for a chuckle.

Yet what Hansen says happened to her that night still inspires her nearly 30 years on as she administers Ufocus NZ, an organisation she founded in 2000. Ufocus NZ catalogues and investigates New Zealand UFO sightings - and it has received 48 reports in the last 12 months.

About a week ago the organisation, based in Tauranga, publicised its work for the first time. Since it featured in news reports Hansen has received 100 emails from people wanting to report sightings. She says most are historical sightings people have only told family members about, but now feel able to confide in Ufocus NZ. A chance to finally get the secret off their chest. It seems they've come to the right person.

When Hansen and her husband came over the brow of the hill that night, the bottom of the valley ahead was out of sight. She still dreams of being able to peek down that valley a little further. What they did see was the whole valley bathed in a bright white light. It was like someone had flicked a switch, but the light was brighter than the brightest sunlight. The car stalled and the couple sat there stunned. On either side of the valley she could see virtually every tree lit up so brightly they had a silvery white colour.

Initially, Hansen and her husband were panicking and yelling at each other. Then they started whispering. Her husband tried to reassure her it was probably caused by possum shooters with a spotlight. Hansen knew that was rubbish.

They sat staring fearfully. She suggested driving back to Gisborne. Anything to avoid going towards the light. Hansen began to notice her arms and legs were feeling numb and tingly. She heard a deep buzzing sound and felt dizzy and faint. She tried to talk to her husband to ask him if he felt the same, but she couldn't speak.

Her next recollection is sitting next to him in the dark, both of them staring out the front window of the car. She grabbed her handkerchief and wiped away condensation from the inside of the windscreen.

"The light's gone," Hansen said to her husband.

"Shall we go now?"

"Okay," he mumbled. They set off and traveled in silence for the rest of the journey.

Hansen felt extraordinarily tired the next day, which she put down to a late night. But her ears were painfully sensitive and she suffered several nosebleeds. She couldn't remember anything about the trip home - not even putting the groceries away.

She tried to discuss the incident with her husband, but he didn't want to talk about it. It seemed to scare him. Hansen couldn't forget it. For a long time afterwards she stopped going out on fishing trips at night. Car lights shining in the windows at night would send her running for cover.

She believes they were abducted by aliens that night, but is reluctant to talk about it, knowing how absurd it sounds.

The late 1970s and early 1980s were a busy time for UFO sightings around Gisborne and the east coast, a period known as the Gisborne "UFO Flap". The Gisborne Herald had a field day with more than 200 reports including accounts of lit-up valleys or hillsides - exactly as Hansen describes - strange aerial buzzing, cracking or exploding sounds, sightings of shiny metallic craft and even sightings of humanoid figures in silver suits.

Reports tailed off in the mid 1980s.

Senior Hamilton air traffic controller Graeme Opie was living in Gisborne at the time, but didn't even hear about it.

He was a young man, doing his own thing, rarely bothering to read the newspapers.

But in March 1995, Opie's own world would change when on the job at Hamilton Airport he saw something he couldn't explain.

At 1.20pm on March 9, Opie looked south of the control tower and observed an unusual object with a trail behind it.

It had an orange tail, its edges sparkling in a way similar to a fireworks sparkler.

"It was definitely not a fireball or meteorite. It was traveling virtually horizontally."

He says when he held out his arm as if to frame what he was seeing, the shiny head of the object would have been 2mm in diameter. He saw the object for about 1 1/2 seconds before it disappeared behind clouds.

He says the object traveled in a 23< arc across the sky in the space of a second. When he lost sight of it he checked with Auckland air traffic control to see if it was registered on their radar screens - it was not.

Using the expertise of his training, Opie has estimated the object was traveling about 39,000 km/h.

Opie had always been interested in aviation and UFOs, but this was a big moment for him; it gave him something concrete to work on.

At the same time as Opie made his sighting, Air Traffic Control Rotorua received three calls about an object in the skies above Bay of Plenty heading west.

The Hamilton tower also received a phone call.

Three minutes before Opie's sighting, two fisherman near Pudney Rock, near Motiti Island, Bay of Plenty, reported the same object. The next day the Waikato Times reported the sightings, quoting school children at Cambridge and a farming couple at Te Kawa.

Opie speaks deliberately and carefully, perhaps as a result of a long career in air traffic control.

He avoids emotional references to his sighting.

"I consider that what I saw from the control tower was a UFO - definitely some sort of controlled UFO or craft. It is very interesting that it did not appear on our radar screens."

Soon after the sighting Opie connected with Hansen and ultimately has become a major figure of Ufocus NZ.

Hansen and Opie are among nine members of Ufocus NZ Network which is spread around the country and provides a formal reporting system of UFO sightings. While some of the 48 reports it has received in the past year were explained by natural phenomena or other conventional causes, most could not be explained, says Opie.

New Zealand has a rich history of UFO sightings. Hansen says for some reason a high percentage of sightings have been around the central North Island and volcanic plateau.

New Zealand's most famous sighting was the "Kaikoura lights" in December 1978. On December 21 the crew of a cargo plane saw strange lighted objects around their aircraft. The lights tracked them for several minutes before disappearing and reappearing elsewhere. They appeared on Wellington air traffic control radar, on aircraft radar and were sighted by hundreds of people.

On December 30 an Australian TV crew onboard a cargo ship filmed a similar event between Wellington and Christchurch. In a world first, UFOs were filmed, tracked by Wellington air traffic control and observed by witnesses simultaneously. Never before had there been such comprehensive coverage. One of the objects followed the aircraft almost until it landed. When the aircraft took off again it was followed by an enormous orb-like object for 15 minutes. Again the event was filmed observed and tracked, and the Kaikoura lights film footage became renowned worldwide.

The Defence Ministry attributed the sightings to lights from squid boats reflected off clouds, unburned meteors, or lights from the planet Venus or trains and cars.

Ufocus NZ is hosting an international conference on UFOs and related topics in Rotorua in September 29 and 30. Hansen shares information with similar organisations all over the world.

Opie tells of a phone call he received the night before his interview with the Times. "I had a guy call me last night who has a sighting in 1948, but sat on it all this time because he didn't want to be regarded as a crank.

"Suddenly we are getting people who are coming out. People who've only ever been able to talk to their family about this but are now saying 'at last I can get this off my chest'.

"If you talk to those people, there's no sensationalism. They are not after media coverage - they just want to get it off their chest."

Can all this talk of UFO sightings be for real?

Opie is measured and careful, but some of Hansen's comments on the Ufocus website seem far-fetched.

A cynic would suggest UFOs appear to follow her around. She saw her first UFO when she was eight and she and her family saw an orange cigar-shaped object hovering over the Bombay Hills.

She recalls seeing a UFO south of Hastings where she remembers feeling the car being lifted off the ground.

In 1978, around the time of her episode driving from Gisborne to East Cape, Hansen recalls being terrified by buzzing and bright lights above their house at night. Again she suffered fatigue, hearing sensitivity and nosebleeds afterwards. Again she hints she may have been abducted.

On another occasion on the East Coast she saw a UFO while riding a horse.

In 1995, 12 days before Opie's sighting, Hansen believes she saw the same UFO. The website says on February 25 at about 10.30pm she felt the sudden and urgent need impulse to go outside her Tauranga house.

"Having experienced close encounters for most of her life, Sue had long ago learnt to follow such spontaneous intuitive feelings which have invariably led to advantageous events or meetings," says Hansen's report on the group's website.

Hansen says she saw a large bright green ball of light heading over the Kaimai Range towards the sea. She then saw another light - this time with a brilliant reddish orange glow. Its descent slowed and the two lights converged. The lights vanished behind Mayor Island.

"It appeared almost as if the green light was 'escorting' the larger reddish light during the final visible part of their descent."

Hansen says numerous sightings have occurred in the Bay of Plenty over the years, especially around Mayor and Motiti Islands.

"Local witnesses of highly strange events have long speculated on the possible existence of an underwater UFO base out at sea beyond the islands."

Does she worry if people think she's loopy?

"That's okay if they're sceptical. If they haven't experienced it I would hope they would have an open mind - but I'm not here to convince them."

She says people expect her to look eccentric and are surprised by her appearance.

"They expect me to have big jiggling earrings and lots of jewellery and a big full skirt."

She says Ufocus NZ has a formal documenting system that doesn't try to make assumptions.

"We are never going to say 'it is' something; we are saying 'we don't know what it is'."

Hansen, who has four children, taught at primary and secondary school for more than 20 years and is an experienced counsellor. She has spoken at UFO conferences in Australia and the US.

Asked why she has seen so many UFOs, Hansen doesn't know.

"Maybe I've just been in the right place at the right time. A lot of people see them but don't talk about it."

Opie says scepticism is just what is needed because it promotes more research. He welcomes it.

He says some of the UFO sightings over the years could be put down to military aircraft being trialled.

"But some of the speeds - certainly with my one - are not explainable by anything man-made. The majority of them had speeds and trajectories and manoeuvres that don't obey the laws of physics.

"The only explanation you can give is that they are not man-made.

"I believe in the theory that we are not alone." He says it is "arrogant" to believe ours is the only planet with life on it.

Both suggest the name UFO has been tainted by suggestions of aliens, just as the phrase "flying saucers" was before that. They say the term is being redefined as UAP (unidentified aerial phenomena).

"You have to get away from ideas of little green men and flying saucers," says Opie."

He is in a position of seniority at the airport but says he feels supported by staff and management. "No one has called me a kook."

Waikato University director of religious studies Doug Pratt says people who believe in UFOs may often be "gnostics" seeking wisdom and searching for knowledge that leads to salvation and enlightenment. He says in a sense UFO believers fit into the category of gnostics as they believe in an esoteric line of wisdom that's not publicly verifiable.

Gordonton-based David Riddell, editor of the New Zealand Sceptic, says Ufocus NZ does appear to have a genuine spirit of inquiry which he approves of. But he is sceptical about UFOs.

"We are aware of how easy it is to misconstrue things, and our understanding of the world we live in is very limited."

Riddell says the universe is an incredibly big place and it is highly likely there are many places that have life.

"But it's one thing to have intelligent life and it's a substantial step to have that level of technological life."

He says there may be intelligent life, but not necessarily life capable of making space ships which can travel to other galaxies. He says it's important to understand the vastness of the universe. For example, even if there were a billion planets capable of sustaining life in the universe, the distances are such they would still have to travel up to 2 million light years to reach Earth.

He says just because something is a mystery, doesn't make it an alien spacecraft. Riddell says UFOs are not the first phenomenon of its kind and refers to the great Zeppelin scare of 1909. In the tense pre-WW1 period in 1909 there was great fear of Germany's Zeppelin airships which were considered a danger to the allies. After news stories reported the issue in New Zealand, between July and August there were thousands of sightings of Zeppelins. In some cases whole towns reported seeing them despite the fact there was no way Zeppelins could be in New Zealand skies.

"People's perceptions are coloured by their social conditioning. In a world where they expect to see aliens they probably will."

Riddell says up to two million Americans have reported being abducted in the last 30 years, which equates to one every few minutes.

He suggests many encounters are more likely episodes of sleep paralysis and hypnopompic dreams - dreams that occur in between sleep and waking. In such instances people imagine things and have some sort of paralysis and often overwhelming terror. Seizures are another possibility.

Riddell says it's a bit surprising to see a new UFO organisation starting up, because the worldwide phenomenon is in decline.

Several such groups in the US and Britain have closed down for lack of support in the last couple of years, a fact recorded in newspaper articles.

Hansen says there is no doubt UFO groups have dwindled, but there's a good reason for this - the growth of the internet.

"What would you rather do on a cold night? Go to a meeting to talk about UFOs or research on the internet?"

She says interest from followers is as high as ever.

Riddell also says with so much information freely available and secrets so much harder to keep, proof of UFOs should have been found by now.

Hansen and Opie see momentum building as governments around the world begin to disclose their files on UFOs. Several countries, including Brazil and France, have done so in recent years.

Both hope the world will get to the bottom of what UFOs are and where they are from.

"If I find out they are from the US military I will be very disappointed," Hansen laughs.

One senses deep down Hansen doesn't have any doubts.

She just has to remember that lit up valley in Tokamaru Bay when she was 23.

"It was as if the light was shining from every direction at once and yet at the same time it was clearly originating from something.

"The magnitude of that light I saw that night, I couldn't begin to describe it in words.

"I would just love to know what caused that."