Search and rescue teams will work through the night looking for survivors following the massive earthquake in Christchurch, Civil Defence director John Hamilton says.
Prime Minister John Key has confirmed 65 people are dead, and the number is expected to climb.
"We have to be prepared to accept that it is going to be a heavy toll," Hamilton said on Tuesday.
He could not say how many people were trapped in buildings, saying information was "patchy".
"There could well be people who are stuck in buildings overnight. I can't confirm, but I would expect that's in all probability the case." Mr Hamilton said an urban search and rescue team from Australia was on its way and was expected to arrive after midnight.
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A team has also been deployed from Auckland and a second team would be sent down as well.
Hamilton said ambulances from other parts of the South Island were on their way to Christchurch hospitals and other centres. He said a large welfare centre had been established in Hagley Park, which would provide shelter for people who could not go home.
"I would expect the civil defence authorities in Christchurch to open welfare centres across the city to take in and support people whose homes are unavailable."
