One-bedroom properties would be sold for $500,000, two-bedroom for $600,000 and three-bedroom for $650,000.

That meant the larger houses were $50,000 more than Labour promised during the election.

A spokeswoman for Twyford said that was because the modelling on the prices had been done two years ago and had now been updated.

The minister confused things further when speaking on the AM Show this morning, repeatedly insisting that the price point would be $550,000 for one-bedroom homes.

That prompted National's housing spokeswoman Judith Collins to accuse him of lifting the price of smaller homes by $50,000 in three days – since the tender documents were released.

Collins said Twyford had given a staunch defence of the new price for smaller homes.

"He was clearly determined, he gave an entire explanation to the public about why he was right and why the prices had changed."

But Twyford's spokeswoman said he had been mistaken and the one-bedroom homes would still be sold for $500,000.

The Government has committed $2 billion to the Kiwibuild programme, which it says will be recycled as it recoups the cost of construction from buyers.