The head of the civil defense said there had been no live rescues since last week and the grim reality was that no more people would be found alive.
Seventy people were pulled out alive from leveled buildings in the city's central business district, when the quake struck at 12.51 p.m. last Tuesday, at a time when the city center was full of lunching office workers and shoppers. The last person found alive was the day after.
The confirmed death toll is 161, with police estimating that the final toll may be as high as 240, making it the second worst natural disaster after the 1931 Napier earthquake which claimed 256 people.
The victims are believed to have come from more than 20 countries, with many being foreign students -- including Japanese and Chinese -- at an English language school in a building where the six floors collapsed on top of each other.
The local mayor said the news made it a "terrible" day for Christchurch.
"We will continue to hold hope that there is a still a miracle out there," Bob Parker said.
More than 1,000 rescuers from New Zealand and seven countries, including Japan, the United States, Australia, and Taiwan, have worked day and night to find any survivors, but had found only the dead after the rescue of a woman in a finance company building last Wednesday.
Rescue officials said a recovery operation will see them move to clearing away damaged buildings with heavy machinery instead of the more painstaking methods used when seeking survivors.
The government has said there will be an inquiry into how buildings in the city hit by last September's force 7.1 quake were passed as safe for use, and whether that was a factor in the amount of casualties.
Preliminary costs of the quake have been put as high as NZ$15 billion ($11 billion), which the government has said is affordable although it may need to borrow more in the short term and change its spending priorities.