Fireball over NZ
© (file photo)

At first Gary Wheaton thought he was looking at a flare, until he saw a plane flying beneath it.

Now the Paekakariki man believes what he saw off the Kāpiti Coast about 1.20pm on Monday was likely a meteor that was also spotted over Nelson.

"It was like a streak of light screaming across the sky," Wheaton said. "It got bigger and bigger and bigger and popped."

Wheaton called his daughter out who got there to see the "huge smoke trail" it left across the sky.

"It just happened so quick," he said.

He initially thought it was a flare from a boat but realised - due to seeing a plane in the sky beneath it - it was far too high.

Police confirmed they were called about what appeared to be a boat flare but said it was more likely it was a meteor.

Nasa describes a meteor as meteoroid that enters the earth's atmosphere, vaporises, and becomes a streak of light in the sky.

Residents in Nelson city and in the small town of Wakefield, 25 kilometres south-west, also reported seeing a meteor with an orange tail blaze a path eastward across the region just after 1pm on Monday.

Ken Allan reported seeing the fireball at about 1.15pm above Nelson, heading roughly east.

"[It] had a long orange tail, came from nowhere, and shot over the Stoke hills," he said.

Duncan Steel, of the Centre for Space Science Technology in Alexandra, said anything able to be seen during the day would have to be large to be noticeable, and would be fairly rare.

"To be bright enough to be seen in the middle of the day the meteoroid (the solid object in a meteor) would need to be a substantial size, like a rugby ball. So not huge, but substantial.

"They often appear to be moving at the speed of a jumbo jet and because of that people assume they must be at about the same height, about 10km up, but actually most meteors would be about 60km to 100km up in the atmosphere. That's where they start burning up."

He said the meteor seen on Monday would have been enough to "light up the night sky" if it had happened later, and would be referred to by the technical term "fireball".

Steel said that the meteor could have been a "natural" meteorite, but said it was also very likely, given the direction it was travelling, for it to have been a piece of "space junk".

"There's 40,000 pieces of space junk being tracked in Earth's orbit right now."

He said all man-made satellites orbited in the direction of the earth's spin, so when they re-entered the atmosphere they moved in an easterly direction.

"If it seemed to be travelling east I would be suspicious and say it seems like space junk ... substantially less frequent [than meteoroids], you'd have a handful a year."

Anyone wanting to confirm their sightings of the meteor can check NASA's official Fireball tracking website here in a day or two, Steel said, as the data would be made publicly available.