The death toll from the Feb. 22 devastating Christchurch earthquake had risen to 159 overnight after four more bodies were recovered.

Police Superintendent Dave Cliff told a joint press conference on Tuesday morning that 11 people have now been officially named and police expect the death toll to reach about 240 once all the bodies have been recovered from collapsed buildings and identified.

Fire Service spokesman Russell Smith said teams had now traveled up to the 10th floor of the severely damaged Grand Chancellor Hotel and confirmed there was no-one inside.

They had shored up a wall at the Christchurch Cathedral to allow teams access to up to 22 bodies inside, he said.

High winds were an issue for search and rescue on Wednesday morning as they posed an issue to already unstable and damaged buildings, he said.

Civil Defence controller Steve Brazier told the conference building assessors were having to break through doors to check some properties for earthquake damage.

Locksmiths were traveling with the teams to repair the doors after they left, he said.

He urged residents to look out for vulnerable people who may have "fallen through the cracks" in the Christchurch disaster response.

The chief executive officer of power company Orion told the conference that 27,000 customers - mainly in the eastern suburbs of Christchurch - remained without power.

He said those suburbs had sustained a "huge amount of damage" to their infrastructure.

Christchurch Mayor Bob Parker said residents of 60 homes in Sumner remained evacuated due to a significantly unstable cliff face above their properties.

Mayor Parker said reticulated water had now been restored to 67 per cent of Christchurch homes.

Mayor Parker said the main road north was now open and work was being done to fix the sewerage system.