WELLINGTON: New Zealand will hold a national memorial service on March 18 to mark the "terrible loss of life" in the Christchurch earthquake, Prime Minister John Key said Monday.

Key said the service would culminate in two minutes' silence at 12:51pm (2351 GMT Thursday), the exact time a 6.3 magnitude tremor tore apart Christchurch on February 22, killing hundreds of people.

"The service will allow people the chance to reflect on the terrible loss of life suffered as a result of the earthquake and the huge impact it has had on our second-largest city," he said.

"This is an opportunity for Christchurch to mourn together. It will also be a chance to celebrate the lives of those who have been lost."

Key said more than 10,000 homes would be demolished as a result of the quake and a further 100,000 were damaged, warning residents many heritage buildings would also be bulldozed after being deemed unsafe. Officials estimate one-third of the city's downtown area will also be razed in a rebuilding process set to cost up to NZ$15 billion ($11 billion) and take a decade to complete. The death toll stood at 166 on Monday, although officials expect the figure to rise above 200.