A construction expert says the Government was never going to avoid underwriting Kiwibuild developers.

The Auditor General has agreed to look into National's concerns about developers being guaranteed a minimum price for already build Kiwibuild homes.

AUT's John Tookey told Kate Hawkesby developers aren't willing to speculate or take on unnecessary risk in the current market.

He says to get the private industry to front up and deliver ahead of the market, you have to underwrite everything they build.

Under the scheme, Kiwibuild guarantees developers a minimum amount for their properties, either by buying unsold stock or topping up shortfalls.