Rescuers worked under floodlights for a second night in central Christchurch as they searched the rubble of buildings for more survivors of Tuesday's earthquake.
However hope was fading for the many people still missing.
[image:1311:half:right]The number of search and rescue personnel at the collapsed Canterbury Television building was increased late on Wednesday night, despite police saying it is unlikely any survivors will be found there.
There are estimates that about 100 people may be in the rubble.
Searchers used sound detectors, thermal imaging equipment and cameras to help them as they continued their efforts through the night.
Police said the effort at the CTV building was now a recovery operation.
Some 320 search and rescue personnel would be working on the ground in Christchurch on Thursday.
Civil Defence said that means the focus can be broadened from just those sites where survivors are known to be trapped.
A structural engineer says there is a significant risk one of the tallest buildings in the centre of the city - the Hotel Grand Chancellor - could collapse and bring other buildings down with it.
A two block radius was cleared around the hotel on Wednesday evening.
Overnight curfew enforced
A curfew remained in place overnight in the central business district, from 6.30pm on Wednesday until 6.30am on Thursday.
The cordon around the CBD is being tightly policed, and members of the public risk being arrested if they are found within the cordon.
District Commander Superintendent Dave Cliff says there were six arrests in the CBD on Wednesday for theft and burglary offences.
Structural engineer Jade Kirk says the damage to the building is irreparable and will need to be demolished if it does not collapse.
