A number of people have been injured at a shopping centre in Hornsby in Sydney’s north after stormy weather smashed glass panes, toppled trees, and reportedly collapsed a ceiling.

Firefighters and ambulance paramedics responded quickly on Monday afternoon to what is being described as a mini-tornado that hit the Westfield shopping centre near the Pacific Highway.

Police told AAP there had been black-outs in the shopping centre and reports of roof damage.

There were reports a cinema ceiling had collapsed and the centre was being evacuated.

Callers told Macquarie Radio they heard loud bangs in the shopping centre, saw debris flying and large trees down and there were reports of cars tipped over in car parks.

A NSW Fire and Rescue spokesman told AAP that firefighters were using handsaws to go through the debris to see if anyone was trapped.

“A roof has collapsed in one of the cinemas,” he told AAP.

The spokesman said the shopping centre had been evacuated.

Paramedics have also been deployed to a library in Hornsby and a demountable building near the railway station.

The spokesman said the demountable had been blown off its foundations.

An Ambulance Service of NSW spokesman said while there was certainly damage, there was no information yet on patient numbers.

A witness, James, who lives near the shopping centre told ABC radio he heard a big roaring sound just before 3pm (AEDT).

“I wasn’t really sure what it was, it sounded like a cyclone or something,” he said.

“So I ran to my back window and I could see all this debris spiralling up in the air like rubbish and stuff.

“It went over pretty quickly but shortly after I just heard nothing but sirens.”

Another witness, Angela, told ABC radio she saw debris going up into what looked like a mini-tornado.

“That went over across the shopping centre and I could see some roofing material, looked like long bits of guttering going up into the sky over the shopping centre,” she said.

“So I think it was mini-tornado.”

It only last 10-20 seconds, she added.