Housing Minister Nick Smith wants Auckland to break out of its boundaries, saying that without change, ownership dreams are being killed.
"If you put a straitjacket around the city and say only land for residential development is in that defined line, you're gifting a massive capital gain to those rural land owners," he said, citing a Flat Bush property bought in 1995 for $890,000 and now on the market for $112 million - a situation he called "obscene".
Land bankers had been encouraged to hold their parcels and strangle supply, the minister said.
"Because they have a monopoly, they are able to make those sorts of profits and the best way to stop it is to actually create a greater degree of freedom," he said, citing the housing accord between the Government and city council intended to improve housing affordability.
"We cannot walk away from the issue that restrictive land supply policies across the world are at the heart of the housing affordability issue," Dr Smith said.