Prime Minister John Key has announced a national state of emergency during an emotional address this morning, in which he told residents the whole country was behind them.
The move was announced following the third emergency Cabinet meeting since the 6.3-magnitude quake struck at 1pm yesterday.
Key said at least 75 people had been killed in the earthquake, and he said the number could go higher.
He called on all Kiwis to pitch in to help people stricken by the quake by offering places to stay or making donations to relief efforts.
This was not Christchurch's test, but New Zealand's.
He told Christchurch residents: "This country is right behind you and we are backing you with all of our might."
"Today I want Christchurch to hear this message: you will get through this. This proud country's right behind you and we are backing you with all our might."
Key said help was flowing in from around the world, and he promised no effort would be spared to rescue people who were still trapped and to help the city rebuild.
"It's quite clear that there will be major rebuilding in the centre of Christchurch," he said.
Key said the scale of the recovery effort was unknown at this stage and would not rule out the cost rising a high as $16 billion, as estimated in some overseas reports. The September earthquake cost $6 billon to $8 billion.
He was expecting a further 100,000 EQC claims from yesterday's quake.
Key said it was too soon to speculate on Rugby World Cup games in Christchurch.
He would to arrive in Christchurch at 1pm and visit welfare centres.