Storm damage in Kurri Kurri, NSW
© Nick HansenA tree down on a car in the main street of Kurri Kurri.
A roof collapse has sent two people to hospital as rain and hail caused widespread damage across NSW, with the bureau predicting more "giant hail" and destructive winds into the evening.

The Bureau of Meteorology warned "giant hail and destructive winds" were possible with thunderstorms over the North West Slopes and Plains, parts of the Upper Hunter and inland parts of the Mid-North Coast.

Areas that could be affected this evening are Port Macquarie, Taree, Armidale, Tamworth, Gunnedah, Moree, Narrabri, Walgett and Lightning Ridge.

The dangerous weather caused the roof of a community centre to collapse in the Hunter Valley town of Kurri Kurri, near Cessnock, just after 2:00pm.

Two people were taken to Maitland Hospital with non-life-threatening injuries while everyone else inside the centre was accounted for.

Snow at Perisher, NSW
Snow at Perisher today, just 25 days from start of summer.
The storm also produced has a massive hailstorm which hit suburbs north of Wollongong.

The weather bureau said golf-ball-sized hail fell at Narrabri about 3:20pm.

Across the state, the BOM has issued severe thunderstorm warnings, a marine wind warning and hazardous surf warning, with the greatest impact likely to be on the South Coast and Illawarra.

The BOM's Mohammed Nabi said the weather would get worse as the day progressed.

"At the moment we do have a severe wind warning for damaging winds along the coastal parts and the higher ground that is expected to effect the Illawarra later this afternoon with south, south-westerly winds," he said.

NSW State Emergency Service spokesman Phil Campbell said storms hit the state's north-east last night, especially around Grafton.

"We are expecting these storms to persist around the south-east of the state today, including the Sydney metropolitan," he said.

"People should ensure they're well prepared and drive to the conditions with potentially hazardous driving conditions today in many areas of the south-east."

'Massive' damage reported in some parts of northern NSW

Stephen Butcher, from Tregeagle, near Lismore, said the damage from last night's storm was "massive".

"I fear for some of my stock, I have thousands of dollars worth of yearlings, two-year-old thoroughbreds in the paddocks," he said.

"I'm hoping they stood up. I saw some of them venturing out when the ferocity of the storms hit.

"I could hear the roof tiles breaking with the force of the wind and the size of the hail. I've never seen anything like it."

Otto Saeck is the owner of Blueberry Fields at Brooklet near Byron Bay and said it was the most severe hailstorm he had seen in 30 years of growing berries in the area.

"It was very very scary. We were sitting in the middle of the house hoping the windows wouldn't break," he said.

"The purpose-built hail nets, we spent over three quarters of a million dollars on them upgrading them three years ago, hasn't stood up to the load and the winds.

"It was like a tornado. We've lost most of the summer crop. We've got to spend hundreds of thousands in repair work.

"We'll prune these hard, that have been damaged, hopefully they'll come back, but if not we'll have to pull them out and start again. It's pretty expensive."