Labour is urging the public to have patience when it comes to KiwiBuild.

The Government's flagship housing policy - to build 100,000 affordable places for first-home buyers in 10 years - has, after a year-and-a-half, only delivered about 84.

"Obviously it's difficult to get things going - it always is when you start a project like that," Labour MP Kris Faafoi told The AM Show on Friday.

"But as the minister has said, he's looking at resetting some of those targets and Cabinet will decide that next June."

Housing Minister Phil Twyford is refusing to make good on his promise to resign if KiwiBuild is a flop, saying he's focused on that reset, which will take place after the delivery of this month's Budget - and could involve a Cabinet reshuffle.

"Until then, I've got my head down delivering the broader housing programme," said Twyford.

National housing spokesperson Judith Collins wants Twyford demoted to a lesser portfolio, suggesting associate commerce - which would see him report to Faafoi.

"It's a flop. Let's just be real here - Phil Twyford has his portfolio for six years in Opposition, had plenty of chances to get his policy right. In fact, what he's done is shown it doesn't work.

"I could have gone out and bought 84 houses with the $2 billion that he got out of last year's Budget, if he wanted me to, and I could have done it a lot quicker."

In fact, she could have bought New Zealand's most expensive-ever home - a Herne Bay property which sold for $27.5 million last year - almost that many times over. Two billion dollars would purchase about 3000 average-priced KiwiBuild homes, but New Zealand also has a construction skill shortage.

Deputy Prime Minister Winston Peters is remaining bullish, saying 100,000 is "easily achievable" - even if Twyford and Prime Minister Jacinda Ardern are resetting their expectations.

"The Deputy Prime Minister is very ambitious for New Zealand," said Faafoi. "Never ignore Winston Peters."

It seems unlikely KiwiBuild will sit on 80 homes for long, with 261 under construction and another 10,000 "contracted and committed to build", according to its website.

Newshub has contacted Twyford for a response to Collins' latest attacks.

New Zealand has a housing shortage numbered in the tens of thousands, data suggests, driving up prices - which KiwiBuild was meant to solve.

Newshub.