Builders say proposed changes to building requirement in Christchurch are a kneejerk reaction which could slow down rebuilding the city.
Christchurch City Council wants to make it compulsory for new houses to meet much tougher foundation guidelines.
It has asked the Government to make the requirements compulsory throughout Christchurch and Banks Peninsula.
Mike Greer Homes says the guidelines will make its new houses about 10% more expensive, which will push prices out of the reach of some families.
But the council says that if someone wants to build a weaker foundation, they will first have to provide a geotechnical report to prove the ground is suitable.