Housing affordability in Auckland is improving even though many Special Housing Areas (SHAs) haven't gone ahead, Prime Minister Bill English says.
Watch Bill English speaking to Morning Report's Kim Hill:
Mr English told Morning Report the Auckland Housing Accord - under which the fast-track housing areas were set up - highlighted the challenges of trying to make private developers build affordable homes, and falling prices were not helping.
Developers in the SHAs got special treatment such as a speedier consent process and re-zoning, and under the system at least 10 percent of the homes they built had to be classed as affordable.
But the head of the Auckland Council's planning committee, Chris Darby, told RNZ last week at least 86 of the 154 of the areas no longer existed.
Mr English told Morning Report affordability was improving because of changes in the market, and due to support from government and council policy.
Some SHAs hadn't proceeded, but they'd been "bypassed" by the Auckland Unitary Plan, in place for 18 months, which was a "much better arrangement", he said.
"It allows the city to grow and in the long-run affordability is all about enough new houses on the ground."
Housing group representatives have said many developers sat on the land, waiting for the Housing Accord to end and the Unitary Plan to come into force, so they did not have to build any affordable homes.
"You'd need to look at the legal terms on which it all occurred," Mr English said. "It does show the challenges of ... trying to inject lower-cost houses into these situations where developers want to see a margin.
"The council in Auckland was always keen to require a certain price for some of the housing. We accepted that was an objective they wanted to achieve - in some cases that hasn't actually happened."
Mr English said it would be up to lawyers to decide whether rules had been broken.
The biggest challenge for developers in the city now was flat or falling house prices, he said.