Both the Greens and National want to double the number of tunnels out to Wellington's eastern suburbs, but the plans couldn't be more different.
The two parties have traded blows over the future of Wellington's transport, but Labour has more or less stayed out of it.
Green Party co-leader James Shaw unveiled a 10-year, $13.6 billion transport package in Auckland this afternoon, calling it the boldest plan to transform how people get around ever seen from a political party.
It included a dedicated walking and cycling tunnel running parallel to the current Mt Victoria tunnel in Wellington, as well as a mass rapid transit tunnel by the zoo.
Shaw said the Greens did not intend to re-negotiate the $6.4b Let's Get Wellington Moving (LGWM) plan if it gets back into Government.
That's something the Greens, National and Labour all do agree on.
LGWM was announced by the Government last year and includes mass rapid transit, doubling the Mt Vic tunnel and walking and cycling improvements.
Shaw said he would continue to push for public transport improvements to be delivered first and for light rail to be put on the new mass transit spine.
Controversy erupted last year amid revelations Associate Transport Minister and Green Party MP Julie Anne Genter's support for LGWM was conditional on mass rapid transit being prioritised before a second Mt Victoria tunnel.
Genter outlined her position in a secret letter to Transport Minister Phil Twyford, which the Ombudsman ruled she was entitled to withhold.
When LGWM was announced, construction on the tunnel was pushed back to the end of the decade.
In policy documents released today the Greens set out a plan to build a new dedicated walking and cycling tunnel at an estimated cost of $100 million.
Shaw said councils would be able to bid for the project through the party's proposed $1.5b Cycle Super Highway fund.
The dedicated tunnel would involve expanding an existing pilot tunnel that runs parallel to the existing car tunnel.
The pilot was excavated in the 1970s to investigate the feasibility of a second Mt Victoria tunnel.
Shaw said the current experience of walking or cycling through the tunnel was "horrendous" due to car fumes and such a narrow path.
National's transport spokesman Chris Bishop accused the Greens of being "totally ideological" and not taking an evidence-based approach when official advice was to build the second Mt Victoria tunnel sooner rather than later.
"Wellingtonians need to know that if Julie Anne Genter is let back near the ministerial benches after the election she will stuff up Wellington transport more than she has already."
Shaw disputed that and hit back at the comment about Genter.
"To me that just sounds like frankly election smack talk. National are obviously not doing very well and getting increasingly desperate in the pronouncements that they're making, so I don't put a lot of stock into it."
"The evidence is that when you try and build your way out of congestion by building more roads, you actually create more congestion."
The National Party has promised to start construction on a second Mt Victoria tunnel within its first term and would legislate for that to happen if necessary.
"I don't think anyone in Wellington thinks that adding a walking and cycling tunnel through Mt Vic is actually doubling the tunnel," Bishop said.
Labour's Transport Minister Phil Twyford said his position has always remained the same.
"LGWM partners will have an evidence-based discussion on the timing of the project after the business cases are completed next year."
The Green Party's plan would also see a new dedicated light rail tunnel near the Wellington Zoo connecting the eastern suburbs via Newtown, funded by central Government.
Trackless trams and buses have been floated as other modes to go on the mass rapid transit spine running from the railway station out to the airport.
But the Greens have campaigned on light rail in Wellington for decades.
"Light rail will provide a fast public transport service from the eastern and southern suburbs able to carry thousands more people than the current bus services," Shaw said.
Twyford said the design of preferred mode of rapid transit would be determined by the business case.
National leader Judith Collins have previously indicated the party is keen on buses.
"Unlike Labour and the Greens, we are not wedded to light rail. We think bus priority and bus rapid transit offers much more flexibility for Wellington, and value for money. In time, that may mean trackless trams," she said.
The Greens have also supported further investigation into extending light rail to Island Bay and converting the Melling rail line to light rail. It would then be extended through Lower Hutt to connect with the Hutt line.
The party also wants to fast-track the Bus Priority Action Plan which it says has been held up by delays in the Let's Get Wellington Moving process.