Inner-city Christchurch building owners say the city's rebuild will be so expensive many of them are looking to take their money elsewhere, including overseas.
The group City Owners Rebuild Entity says insurance payouts will not cover demolition and construction costs, and banks will not lend on developments with no tenants.
It wants low-interest loans for building owners, funded by investors buying government-guaranteed bonds.
Property developers Dean Marshall and Ernest Duval say without incentives, many landlords will take their money to other cities or countries.
Building owners and heritage supporters meeting on Monday night said demolition has gained pace since damaging tremors on 13 June.
Showdown over heritage inevitable - MP
Central Christchurch MP Brendon Burns fears accelerating demolition is making a showdown over heritage inevitable.
Mr Burns, a Labour MP, says a flash-point will emerge within weeks - perhaps over The Press offices or the Edwardian Whitcoulls store.
"People of Christchurch will rally around particular causes and particular buildings. We need to decide what it is that is the line in the sand for us.
"We know we can't fight for every building, but somewhere soon I think there's going to be a building that is lined up for demolition which we just think is too ghastly a prospect, and I'm sure that's going to come to the fore pretty soon."
Mr Burns says a high-profile fight would alert the public that saving heritage buildings cannot wait for a new central city plan to be finalised a year from now.