A Christchurch hotel worker, who was not identified, told the New Zealand Herald newspaper that a sound like an explosion had shaken nearby buildings.
Evacuations were being carried out while police remained on the scene.
Frantic neighbours and passersby helped drag the survivors out of the debris.
Messeha could see flames and smoke coming from a house over on the next street, Marble Court.
"Safety experts have been going from house to house within the outer cordoned area to ensure these homes are safe for people to return to", says Canterbury Metro Commander Superintendent Lane Todd.
"We're working the street over and we just heard the biggest bang we've ever heard, it felt like an quake". A further 17 properties have been impacted by debris.
"I saw there were people hurt so jumped the fence and started helping people, pulling them out of the house and it was pretty chaotic really", he recalled.
However, on hearing the loud bang, some people expressed worries of gunshots as the city is still recovering from the trauma of New Zealand's deadliest terrorist attacks in history which killed 51 people on March 15 by a gunman in two Christchurch mosques.
"I was picking up a couple of ladies and putting them over my shoulders and onto the grass and [covered] them in blankets". Police did not identify the cause of the incident.
"It was greater than an quake, you'd think a bomb had gone off", the newspaper quoted the employee as saying. Authorities are still investigating the cause.
A bystander says the debris is spread across the road.
"It was just a lot of rubble ... the house is no longer a house, it's half a house", he said.
A neighbour who lives one block over said the explosion shook his house and knocked items off his windowsill. We just got them out, they looked in quite a bit of shock, had burns and stuff. Unlike many other news organizations, we have not put up a paywall.
He said windows in other houses in the street had been blown out, while garage doors had caved in.
"We've had housing insulation raining down on our property so something's obviously had quite a large explosion".
Power has been turned off in the area as emergency services work to contain the situation.
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They added: " Warren is beloved by all who worked with him during an impressive 25-year career in television and motion pictures". The Ministry of Labour is said to be now investigating the situation to make sure the accident was just that.
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