Prime Minister John Key says Christchurch's new central business district will be a ''very livable'' compact city centre with distinct precincts.

Key and Earthquake Recovery Minister Gerry Brownlee will unveil a blueprint for central Christchurch, developed by the Christchurch Central Development Unit, at 6pm today.

The unit was set by the Canterbury Earthquake Recovery Authority (Cera) in April to determine the location of key projects including a new convention centre and sports stadium.

Key this morning said he was confident the unit, Christchurch City Council, Government, engineers and stakeholders had got the vision for Christchurch right.

''I'm quite excited about what I see,'' he told TVNZ's Breakfast programme. ''Because you are starting from base zero, you've got the capacity to do what most cities don't do.''

The blueprint retained Christchurch's green "garden city" feel and provided lots of pedestrian areas.

''There are various precincts and so they are really trying to make sure that things like the stadium and high performance sport, health are all in their own precincts but very much within the CBD broader area.

''So it will be very livable city.''

The blueprint is expected to kick-start the rebuild as investors and developers plan around the location of new major facilities.

Brownlee yesterday said the plan would include spending by the Government to encourage the private sector to invest in the rebuild.

The Government had already spent $5.5 billion on the rebuild so far and Brownlee said taxpayers could have to fund a further $7b.

However, Key said that was a worse case scenario.

The Government would ''step up ... and provide additional funding and there would also be funding from the council and private sector.

''If it is the health precinct and the hospital, that would fall pretty squarely on the Government, others are more debatable. It will depend on what civic assets (Cantabrians) want.''

Debate would ''rage for some time'' on whether there should be a covered stadium, he said.

''My own personal view is that it should, given if you take a 100-year view of Christchurch and their love of sport.''

The prime minister acknowledged there was still a lot of frustration for people with homes in TC3, the technical category where further liquefaction was considered possible and specific geotechnical investigations and foundation designs are required.

A rally of TC3 homeowners was expected to be held this afternoon.

Key said progress was being made.

''They have our 100 per cent support. But I understand the issues they are going through and we're doing everything we can to speed that up.''

- © Fairfax NZ News