BNZ's chief executive has apologised on behalf of the bank for the "more inflammatory" comments made by his chief economist.

Tony Alexander, BNZ's chief economist, sparked debate after penning a newsletter, sent to subscribers, that said young people shouldn't blame Baby Boomers for house prices - and should cut down on coffees to help finance their first purchase.

After media reports and a backlash from some on social media, BNZ's chief executive Anthony Healy said he did not support all of the comments made by Alexander.

"I don't support Tony's [references] to meth houses etc, not helpful, but point is we have a housing affordability crisis so debate on baby boomers vs gen Y doesn't help," Healy wrote on Twitter.


"We need joined-up solutions from council, govt, private sector and NFP's, and yes, I apologise, on behalf of BNZ, for Tony's more inflammatory remarks."

In his newsletter Alexander pointed to structural changes that had driven house prices, including the relative return on property and low interest rates.

Young people wanting to buy should buy a "dunger or even a meth house to strip, and do it up", Alexander wrote, and "basically be prepared to do what the Boomers did in many instances".

"Start out in a desolate new suburb of clay soil far from work, do up a piece of shite, or build and live in what will become your garage whilst building the rest of the house around you in the following few years.

"And how to finance it? Go to cafes and spend as much on lattes, muffins, frappes, wraps, etc. as often as the Baby Boomers did."

Act leader David Seymour's response typified much of the feedback to BNZ and Alexander: "You'd have to give up 9,400 lattes, (or 26 a day) just to keep up with a year's increase in house prices," Seymour tweeted.

The Act leader later issued a press release accusing Alexander of "letting down his profession".

"His focus on feng shui and cat whispering shows he's less interested in reality than he is in perpetuating vapid stereotypes of millennials. He should remember his qualifications before his next flippant rant against young people."

BNZ's PR team posted a response to Alexander's comments, saying the bank knew it had never been more difficult for young people to buy their first house.

"Tony's comments were typically provocative and it reflects his personal views rather than the view of BNZ as a whole.

"There are many causes of the housing affordability crisis and undoubtedly, as many commentators have said, the biggest is a lack of supply, particularly in Auckland. This is why we have been supportive of ways to increase supply, like Auckland's Unitary Plan."