The eastern side of Auckland Harbour Bridge where the Additional Waitemata Harbour Crossing tunnel is planned to be built.

The Government has given its first-ever clear indication it will help fund a rail link to Auckland's North Shore.

The announcement appeared in the Auckland Transport Alignment Project (ATAP) plan released on September 15 and states "Waitemata Harbour crossing improvements, including mass transit upgrade of Northern Busway" are a priority during the 2030s.

The report is significant because it is the first time the Government, Auckland Council and New Zealand Transport Agency (NZTA) have indicated together there will be a "mass transit" component to the Additional Waitemata Harbour Crossing (AWHC).

SUPPLIED An artist's impression of a light rail system on Auckland's Queen Street. Could we be seeing the beginning of such a system now?

The AWHC will be a $4 billion tunnel under Auckland Harbour to be completed around 2030.

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The ATAP report joined together all the major funding contributors to Auckland transport infrastructure: Ministry of Transport, NZTA, Auckland Council, Auckland Transport, the Treasury and State Services Commission.

Auckland Councillor from the North Shore Ward, Chris Darby, says the term "mass transit upgrade" of the harbour crossing essentially means light rail - not additional buses.

"It shows what I am interpreting as rail to the Shore because it's 'mass transit' which is only really a type of rail," Darby says.

"I'm not picking that to be a heavy gauge rail, I'm picking that to be a light rapid transit, contemporary trams, to the Shore.

"For the first time in any document that I've seen, there is reference to the Waitemata Harbour Crossing improvements including mass transit upgrades of the Northern Busway."

However, TransportBlog spokesperson Matt Lowrie says, while he "struggles to think how 'mass transit' would be just busses", rail to the North Shore is still not absolutely locked in.

"I understand that for some people there's an ideological opposition to the word 'rail' rather than just saying 'mass transit'," Lowrie says.

"But yes, it's a way of saying 'rail', it almost certainly will be rail, but they just don't want to say it yet.

"There's still work to go in terms of people within government agencies accepting rail as a viable solution.

"Rail is the leading candidate though."

Auckland's future public transport network set out in the ATAP has "mass transit" of some description extending in a line from Britomart travelling North to Orewa.

There is also a planned public transport line shooting off from Akoranga to Takapuna.

Councillor Darby was, however, keen to stress a $4 billion shortfall in public transport funding needs to be resolved over the next decade.

"From 2018-28 we have $4 billion of funding to find which is currently not identified in council or government budgets," Darby says.

"In the next year Council and Government will need to dig down and come to agreement on non-ratepayer alternative funding tools.

"All these projects that are identified in this document, and the decades they're in, they're all subject to robust business cases.

"They are likely to move, some up, some down as we progress."