A woman in a wheelchair was trapped with gas leaking into her house after a demolition job next door went horribly wrong.

Fire and Emergency spokesman Paul Radden said the house, on Moa Rd, was being demolished when it fell onto the house next door about 7.45pm.

Two crews were at the scene, working to help anyone trapped inside.

He said the collapse had blocked access to the neighbouring house and ruptured its gas line.

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Neighbour Kate Paterson, who is in a wheelchair, was at home when the house's concrete wall was pushed down across her driveway and part of a chimney crashed through her bedroom wall.

The collapse cut a gas line and she could hear gas "hissing" into her property. But with the driveway - her only escape route - blocked, Paterson was trapped. She told her children to leave, contacted the fire service and waited to be rescued.

She now has a big hole in the side of her house and no where to go, as she requires a motel with wheelchair access.

"All day we've been calling the owner asking him to come on site. We told him it was unsafe," Paterson said. "I called Worksafe twice to register a complaint. We knew it was going to fall."

"This was horrific and totally preventable."

Neighbours told the Herald they had growing concerns throughout the day as the demolition proceeded.

The neighbours said they repeatedly called the owner of the decrepit concrete house to tell him the demolition was unsafe and needed to stop. Worksafe was also contacted at least five times, they said.

The neighbour on the opposite side, Stan Schwalger, could see part way through the demolition process that the wall on Paterson's side was out of plumb and would fall across her driveway.

"He was yelling at them to stop, not to pull the wall over," Paterson said.

At one point, Paterson said, one of the workers came over and said that neither they nor their foreman knew what they were doing.

"He told us don't be in that house when it comes down."

The road was blocked off for around two hours as workers fixed the gas leak and dealt with damaged power supplies.

Prime Minister Jacinda Ardern - who lives nearby - reportedly drove down the street but was turned around by emergency workers.