A plan to build a new city with housing for 500,000 people on farmland to the south of Auckland has piqued the interest of the new Labour-led Government.
The idea of a scale housing development at Paerata, a small settlement immediately to the north of Pukekohe, was presented in a discussion document at an Infrastructure New Zealand conference on Friday.
New houses would be built near an existing rail connection, which would be electrified all the way to Auckland's CBD and have two lines, one for passenger trains and one for freight, Infrastructure New Zealand chief executive Stephen Selwood said.
Prefabricated housing could be used, he said.
He said the plan was a good fit with Labour's KiwiBuild policy, which seeks to build more affordable housing, and Labour's Housing and Urban Development Minister Phil Twyford was aware of it.
On Sunday Mr Twyford appeared open to the concept, tweeting "let's plan for growth, building around transport [infrastructure] and all things communities need, [including] affordable housing".
Mr Selwood told NZ Newswire the development would be so large it would be attractive to international developers who currently did not look at New Zealand.
The city could eventually extend northwest to Karaka and across the Pahurehure Inlet to Weymouth.
Mr Selwood said the concept had been floated by unsuccessful Mayoral candidate John Palino and also drew from developments like Springfield, southwest of Brisbane.
"We have another million people expected to be in Auckland by circa 2050," he said.
That was going to clog the city up.
The plan envisages initially about 30,000 houses. By 2050, there would be tens of thousands of homes serving a population of 500,000 people within 30 minutes of central Auckland.
He said some of the farmland was currently not zoned for residential and some was.
"The value of the land unzoned is about a tenth of the value of the land that is zoned. There is a real opportunity here for Government, council and the existing landowners to partner," he said.
The city would be a mixed development with high and medium density housing. Some of the land had views of Manukau Harbour where less dense and higher value housing could be built.
The land is south of the flight path of Auckland Airport. Long term a harbour crossing from Karaka to Weymouth could open a new corridor to the airport.
Auckland Mayor Phil Goff will travel to Wellington next week to meet Prime Minister Jacinda Ardern, Finance Minister Grant Robertson and Mr Twyford.