An impression of the light rail system passing Wellington Zoo, having just emerged from a proposed Mt Albert tunnel.

The chances of Wellington getting a billion-dollar light rail system are looking good, mayor Justin Lester believes.

He reckons there is a "strong likelihood" of the long-talked-about project happening, after the Government's latest transport policy announcement prioritised rapid rail above state highway upgrades.

Plans have already been drawn up for a "spine route" from the railway station to Miramar, taking in the zoo and the airport, and it could all happen within the next nine years.

SUPPLIED The orange line is a route very close to the one proposed for a light rail system from Wellington railway station to Miramar, taking in the hospital and airport. The green line is another proposed mass transit option.

A second spine could follow, with options linking to Johnsonville or the ferry terminal.

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The proposed spine route would take congestion away from the Mt Victoria tunnel and the Basin Reserve, which have remained the source of Wellington's traffic problems since the rejection of the Basin flyover project in 2014.

SUPPLIED A schematic version of the route, as it might look to travellers in a light rail carriage - though by the time it's running, it might have the right spelling of Courtenay Place.

It would head from the station along Featherston, Wakefield or Victoria streets to Taranaki St, going underground at Mt Cook from Wellington High School to Adelaide Rd, near the southern end of the Basin.

It would then take in Riddiford St and Mansfield St, head across the top of Newtown Park past Manchester St, and enter a second tunnel under Mt Albert, opposite the zoo, to Coutts St in Kilbirnie.

From there, it could enter a third tunnel under the airport runway, and continue to Miramar.

CAMERON BURNELL/STUFF Wellington Mayor Justin Lester believes there is a "strong likelihood" the city will get a light rail system.

Wellington city councillor Chris Calvi-Freeman, who holds the transport portfolio, said he had pushed hard for light rail as an integral part of the city's transport future.

"If it happens, it will not be a return to trams, with light rail going everywhere," he said.

"We envisage a single spine route from the railway station to the airport to Miramar, and this would run via Newtown, through a single tunnel under Mt Albert, opposite the zoo.

ROSS GIBLIN/STUFF Wellington city councillor Chris Calvi-Freeman says the proposed route would generate all- day patronage and could be rolled out within nine years.

"My prediction is the light rail has a very high chance at succeeding."

Lester said he had been in discussions with the Government for some time. "I look forward to working with the Government further to get a more modern public transport system for Wellington and improve the network."

Transport Minister Phil Twyford said decisions on specific projects were made by the New Zealand Transport Agency (NZTA).

The agency was consulting on transport options for Wellington, including light rail, as part of the Let's Get Wellington Moving (LGWM) project.

Greater Wellington regional councillor Roger Blakeley, who is part of a working group looking at public transport issues, said light rail was the best solution for getting the city moving.

"Light rail would have the capacity for 12,000 people per hour, which is three times the capacity of two Mt Victoria tunnels."

Fellow councillor Sue Kedgley, who is on the same group, said: "It's the only way to avoid paralysing congestion in Wellington, which will ruin our city."

Associate Transport Minister Julie Anne Genter​ said Wellington now had the opportunity to make the case for investment, from the $4.7 billion earmarked by the Government for rapid transit projects in major urban centres.

However, National transport spokesman Jami-Lee Ross doubted light rail was realistic for Wellington, given that funding for mass transit would drop off once light rail was completed in Auckland.

"I can't see how light rail in Wellington could possibly be afforded under the mass transit allocation that they've put into the [Government policy] statement," he said.

Let's Get Wellington Moving programme director Barry Mein said a "a fair swag" of the Government money would go to Auckland initially. But light rail was "in the mix" as part of the group's planning.

Fair Intelligent Transport Wellington (Fit Wellington) spokesman John Rankin believed "all the pieces were lining up for a very positive outcome for Wellington".

"We have the opportunity to avoid the mistakes that Auckland's made, and it's really up to us to seize that opportunity."