Flat house prices prove there's no crisis - National housing spokesman Michael Woodhouse

National's housing spokesman Michael Woodhouse says flatlining property prices in Auckland prove there is no housing crisis.

Sale prices in Auckland have stagnated in the last few months, after years of double-digit growth. The previous National-led Government called housing affordability a "challenge", refusing to call it a crisis.

Asked by The AM Show host Duncan Garner on Monday morning what it would take for National to admit there was a crisis, Mr Woodhouse said: "Well, I think what you would see is runaway house price inflation."

Housing Minister Phil Twyford has commissioned a report into New Zealand's housing problem, saying figures he's received from the Ministry of Business, Innovation and Employment show there's a shortage of about 71,000.

Prime Minister Jacinda Ardern told The AM Show on Monday the goal is to get a concise summary to help the new Government decide where to focus its efforts.

"One of the things that we really pushed hard for when we were in Opposition was a sense of the scale of what we were facing with the housing crisis. Since we've come in there's been some revelations of the shortfall of housing stock across the country being closer to 70,000."

The latest figures from Auckland Council show increases of around 45 percent in property values since 2014. Prices in many parts of the city have doubled since the global financial crisis nine years ago.

"What we want to do is give those experts - who have struggled themselves to get access to that data to do this analysis - access so they can produce for us a concise report that talks about all of the areas the evidence says we need to be targeting," said Ms Ardern.

Mr Woodhouse said Labour's spent the last few years saying it has "all the answers", and is wasting time and money.

"I'm confused, really. I would have expected Phil Twyford to come out with something a bit more tangible than just another committee. We know the views of those three very learned people, but we have no idea what the committee is going to provide the minister that he doesn't already have."

One of those three people is Salvation Army policy analyst Alan Johnston. His views on the matter are largely set in stone, but he hopes the report will make clear the scale of the problem and what needs to be done.

"I think it is a crisis. I think in some parts of the housing market - particularly the Auckland rental market, but also elsewhere - people are really struggling even to get a roof over their heads. For them it's a crisis, and the extent of that will only become apparent once we've done this work."

He blames not just the previous National Government's refusal to block foreign buyers, but Labour too.

"Under the [Helen] Clark Government, the Salvation Army was advising her and [Finance Minister] Michael Cullen to spend $1 billion on state houses, but they didn't. They laughed at us."

Mr Woodhouse says thanks to National, another 102,000 homes are due to be built in the first term of the new Government. But Mr Johnston says most of them won't be affordable.

"It's so much more lucrative to build expensive stuff. The reality is that filters down into high rents families can't afford, having to crowd into shared housing."

Mr Woodhouse disputes that, saying if homes weren't affordable, they wouldn't sell.

"It depends on what you define as affordable. If a house is purchased, it's certainly affordable for someone. But I do accept there weren't as many houses in the lower-cost bracket that we need."