A New Zealand Urban Search and Rescue (USAR) team made it to the fifth floor of the Hotel Grand Chancellor in Christchurch today but could not get past the fifth floor because the stairwell is damaged.

A week after a devastating earthquake struck Christchurch, killing at least 155 people, efforts continued to rescue people and recover bodies trapped in a number of ruined buildings in the central business distract.

A Fire Service spokesman said a second concrete pour had been completed today in the stabilisation efforts at the teetering 26-storey Grand Chancellor and teams had now entered the building.

"[They] made it to the fifth floor but the stairwell does not allow further access. We still have serious concerns about the integrity of the building," the spokesman said.

The efforts at the Forsyth Barr building were described by the United States team as a "major technical job", which was expected to take about three days.

There were no stairs available below the 10th floor and the USAR team had to use lines to descend down the stairwell.

At the CTV building, which housed an international language school, New Zealand, Japanese and Chinese teams were still working on what was a very slow and technical operation and required good daylight visibility to progress.

A steel support structure for Christchurch Cathedral currently being constructed by engineers was expected to be finished overnight and put in place tomorrow morning. A New Zealand team will then go in and there was also an external rubble pile to be searched.

At the Pyne Gould building, where there are known to be casualties inside, the United Kingdom and New Zealand teams estimate at least another four days work.

"The potential for asbestos to be an issue on some sites is being considered," the spokesman said.