The Government has confirmed a proposed men's prison in South Auckland will be built as a Public-Private Partnership.
It has called for expressions of interest from the private sector to build the 1000-bed prison in Wiri.
Tenders will be called to design, build, maintain and operate the prison for 25 years.
At least four groups are expected to bid for the project, including local construction companies and overseas operators.
The Government says overseas experience suggests a PPP will reduce the cost of building and running the prison by 10% or more.
Previous estimates have put the cost of building Wiri at about $300 million.
The successful bidder will pay the cost of building and operating the prison in exchange for periodic payments.