The Transport Agency is considering a public private partnership for the construction of Transmission Gully, north of Wellington.
Papers obtained by Radio New Zealand show the agency is developing a business case for public private partnership (PPPs) for both Transmission Gully and the Huntly bypass section of the Waikato expressway.
Green Party transport spokesperson Julie-Anne Genter says when such arrangements have been used for roading projects overseas, they have not gone well.
She says PPPs are just a convienient way for the Government to put off the debt so it doesn't show up on its books.
But United Future leader and Ohariu MP Peter Dunne says he is very pleased that Transmission Gully is being considered for a PPP.
He says while there have been some overseas examples of PPPs not working on roading projects, it all comes down to how the project is constructed.