The Government cannot guarantee tens of thousands of new houses planned for Auckland will be affordable.
Finance Minister Bill English says while it would be the Government's preference to provide medium and affordable housing, none of the new houses are subject to any specific threshold requirements.
"That's a matter of detail project by project," he said.
"Housing New Zealand is using economies of scale to get lower priced housing. So we would prefer that the housing is built at a cost which is affordable."
Labour's Housing spokesman Phil Twyford says it's not good enough.
"There's no guarantee those homes will be affordable nor that they'll be earmarked for first home buyers," he said.
"If you don't do that you see what we've seen in Hobsonville and that is huge publicly owned assets being converted to private home ownership, half of those houses are being snapped up by speculators."
The Government has revealed Housing New Zealand will embark on a large scale building project aimed at delivering around 30,000 new homes in Auckland.
Mr English says the rollout was only made possible through Auckland's new Unitary Plan.
"Prior to the Unitary Plan, Government could only build around 3000 more houses in Auckland. Once the new plan is in full operation, we will be able to build tens of thousands of houses - could be up to 30,000 of more," he said.
National is rejecting any assertion it's replicating Labour's KiwiBuild policy which would see around 100,000 houses built over 10 years.
"We've now got the legal ability to build another 30,000 or so, maybe more on that land, and we'd be silly not to do it when there's strong demand," Bill English said.
But Mr Twyford says National's latest housing announcement is "KiwiBuild ultra, ultra, ultra-light."
"These guys are so humiliated by the abject failure of their housing policy to deliver actual housing that people can live in that they've now had to do an embarrassing u-turn."
Mr English says it's easy for Labour to make promises, but much harder to walk the talk.
"We criticise the Labour policy which is all about setting up Government departments to do things it can't do 'cause we've had to deal with the reality and it takes years to get larger scale developments up and going just ask large scale developers how long it takes."
"So they can say what they like because they don't actually have to meet the test of actually getting something done which we've had to."