"He's approved an awful lot of ugly housing, and by the way - what's really ugly is people having nowhere to be, nowhere to stay," she said.
Last month Labour and National decided to join forces to neutralise the politically vexed issue of trying to build more housing by allowing more development in cities. Under their plan, developers will be able to build up to three homes of up to three storeys on most sites without the need for resource consent.
Since doing the deal with Labour, Collins has argued the case for planning changes by saying that homelessness is far worse than building dense housing - and she is not convinced that the new housing will be ugly.
"It's also really important to understand that there's not really much difference in what the Government and us have agreed to on housing that what's already in the Auckland unitary plan," Collins said.
"The fact is, what is really awful is people living on the streets and kids growing up in motels," she said.
Collins did admit that MPs have received a volume of correspondence from constituents from people concerned about the housing changes.
"I'm an Auckland MP, so we all hear that but we also hear from people that their kids not being able to buy a home is destroying their reason to want to live in New Zealand when they can buy one in Australia much cheaper," Collins said.
She would not say how she talked to MPs concerned about the housing changes, saying conversations between the leader and members of her caucus are confidential.
Some parts of Auckland council have taken a strong line against the proposals.
Mayor Phil Goff said Labour and National's plans are worse than what cowboy developers are already putting up in places like Takanini and Manurewa, and leave the council with less control.
"The focus is really about bulk and location, not architecture and design," said John Duguid, council's general manager of plans and places at a recent meeting.
Orakei Local Board chairman Scott Milne said the plan was "a scorched earth policy to build Soviet-style blocks".