There are now 55 bodies in a morgue and another 20 being transported there following the 6.3-magnitude tremor.

Police have said there is "incredible carnage right throughout the city", with "bodies littering the streets".

More than 300 people are still missing. Forty-eight were pulled out from collapsed buildings alive overnight.

The earthquake struck at a shallow depth of 5km (3.1 miles) on February, when the South Island city was at its busiest.

It was Christchurch's second major tremor in five months, and New Zealand's deadliest natural disaster in 80 years.

More than 500 search and rescue personnel, police, fire service staff, soldiers and volunteers worked throughout the night to find survivors trapped under the rubble, many using only their bare hands.

Later, officials said a total of 300 people were believed to be missing, but details are unclear and officials are currently trying to refine that list. Some people may simply not have been able to contact friends and relatives.

The ministry of civil defence said 22 people alone were missing in Christchurch Cathedral, which lost its spire and a section of roof.

Twenty-four others have meanwhile been rescued from the Pyne Gould Guinness building and dogs have detected another seven still alive. The earthquake flattened the four-storey structure where hundreds worked.