The government is considering fully funding a light rail network in Auckland, reaching from the airport to the North Shore.
The projects were listed as potential candidates for taxpayer funding by classifying them as State Highway projects, in a report prepared by the New Zealand Transport Agency (NZTA).
The report, which was obtained by the Green Party under the Official Information Act, listed $9.1 billion worth of Auckland projects, most of which would traditionally be jointly funded with the Auckland Council.
The June report pre-dated the less-detailed September release of the government and council's joint strategy to tackle the city's needs, the Auckland Transport Alignment Project (ATAP).
While ATAP and the council continue to use the vague phrase "mass transit" to describe new links to the airport and across the Waitemata Harbour, the NZTA report called them light rail projects.
However, "mass transit" remained the official public description, because light rail was still to win a value-for-money comparison with some form of dedicated bus route.
The NZTA report priced light rail to the North Shore at an estimated $1.1bn, and to the airport at $1.45bn.
Green Party transport spokesperson Julie Anne Genter has already urged the government to adopt the full funding of urban rail projects, rather than continuing a system that favours road-building.
Auckland mayor Phil Goff has also backed light rail through central Auckland, although the council itself was yet to take a stance.
Another part of the NZTA report to use more precise language than ATAP has done publicly, was how the $4bn gap in funding for the first decade of work should be plugged.
"It is recommended by ATAP that a variable network price for the entire system should be the ultimate goal," it said.
That phrase is generally used to describe some form of electronic user charge.
The public version of the final ATAP report referred less specifically to "smarter pricing".
The NZTA report said the council and government ATAP group should report back by the second quarter of next year, with recommendations and how to go ahead with them.
NZTA estimated it would cost $4.3bn for the government to fully fund the first decade's list of projects.