Twenty Chinese students at an English language school in Christchurch are missing following the massive tremor, Beijing says.

The families of the many missing Japanese students feared killed in the collapse of the CTV building have told of their anguish.

Hundreds of people displaced by Tuesday's earthquake have set up camp at Christchurch welfare centres and more are flooding in.

A desperate plea for rescue by six Filipino nurses trapped inside the CTV building have emerged following fears up to 120 people are still entombed in one of the focal points of Christchurch's deadly earthquake.

A 52-year-old man is in a stable condition after having both legs amputated by a visiting surgeon at the PGC building.

Smashing his way into his devastated home today, Christchurch man Ed Langston appeared somewhat resigned to having lost his house and business in Tuesday's deadly earthquake.

Police have delayed releasing the names of those confirmed dead and for whom there are serious concerns.

Rescuers will do everything humanly possible to find any survivors of Tuesday's destructive Christchurch earthquake, say police.

There is no possibility of survivors in the rubble of the Christchurch Cathedral, police said this afternoon.

There are 76 dead in the temporary morgue set up by police in Christchurch and more coming "in ones and twos", Police Minister Judith Collins said as she praised the efforts of rescue workers this afternoon.

Police and security staff are worrying about the possible further collapse of building facades.

More bodies have been recovered from the collapsed CTV building in Christchurch.

Personnel at the PGC building in Christchurch have switched their focus from trying to find survivors to recovering the dead, the company says.

Rescuers have found no survivors at two Christchurch CBD buildings where signs of life were reported this morning, the Fire Service says.

The family of a woman feared dead in the earthquake has suffered another cruel blow with her home being burgled while her children waited for news.

Search and rescue staff are moving into the suburbs of Christchurch looking for the dead and injured from Tuesday's earthquake. The official death toll this morning stands at 72.

Prime Minister John Key has not ruled out imposing an earthquake levy similar to the flood levy brought in Queensland.