UPDATED 10.36am The Government has opened the door on major new social housing plans in Christchurch.

It''s proposing to transfer up to 2,500 state houses in the city to community housing providers.

Housing New Zealand Minister Bill English said today's announcement signals the market-sounding phase of the commercial process.

The proposal would see Housing New Zealand properties, mainly located in the suburbs of Bryndwyr, Riccarton and Shirley, subject to the transfer.

Labour MP Phil Twyford's questioning why the Government's continuing with the policy, when similar transfers in Invercargill, and this week in the Horowhenua, have fallen through.

"I don't know why they don't just let it go. Give up this ideological crusade and get the state out of state housing and get on with the job of building the thousands of new houses that Kiwis desperately want."

The Government is promising tenants in affected properties will retain their current rights.

The details show successful bidders will enter a 25-year contract with the Ministry of Social Development to provide housing places.

The deal states the properties can't be on-sold and must remain in use as social housing unless the Government agrees otherwise.