The Government is revising its estimate of the cost of rebuilding Christchurch and now believes it will exceed $25 billion.
The Treasury originally put the cost of reconstruction following the earthquakes at about $15 billion.
Earthquake Recovery Minister Gerry Brownlee said the bill for the rebuild is climbing and the Government should have a new estimate by next month.
"What it does indicate, though, is the need for us to have robust cost-sharing arrangements with the Christchurch City Council, arrangements that are sustainable for the city and for ratepayers as well as for Government contributions."
Meanwhile, Mr Brownlee said about 727,000 different insurance claims remain to be settled through the Earthquake Recovery Commission.
He said the biggest earthquake the commission had previously dealt with was the one at Inangahua on the West Coast 45 years ago, when more than 10,000 claims were lodged.