The National Party has launched a campaign to bring forward construction of a second Mt Victoria tunnel for Wellington, but is playing coy on an election promise.
It includes a petition, billboards at the Basin Reserve and a Facebook campaign.
National's transport spokesman Chris Bishop would not commit to an election promise today to bring forward construction, but indicated an announcement around the tunnel would be made next year.
"This is a project that Wellingtonians want, one that they need, and a project they have waited far too long to have delivered to them. It will deliver better public transport through to the eastern suburbs, it will unclog this congestion point."
Bishop said transport generally in Wellington would be a "massive election issue", pointing to the Melling Interchange and Petone to Grenada Link Rd as well as the tunnel.
Transport Minister Phil Twyford agreed the tunnel was a critical component.
"That's why we included it in the Let's Get Wellington Moving package after the last government failed to commit to building it at all. They had nine long years to build it but got distracted by a Basin Reserve fly-over nobody wanted."
LGWM partners would have an evidence-based discussion on the timing of the project after business cases were completed, he said.
Wellington Central MP Grant Robertson said he was "comfortable and confident" with the position reached.
ANALYSIS: National takes the tunnel to Election 2020
Wellington's new mayor used the second Mt Victoria tunnel controversy to his advantage in local body elections and National is preparing to do exactly the same in 2020.
Initial business case work for the big projects in LGWM aren't expected to be completed until early 2021, leaving the party with plenty of scope to fill that time with a campaign to bring the tunnel's construction forward.
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The tunnel issue has been kept alive by the Julie Anne Genter secret letter hoo-ha and subsequently with the ousting of one-term Labour mayor Justin Lester.
National sees Andy Foster's rise to power as a mandate from the people of Wellington for a second tunnel to be brought forward.
National list MP Nicola Willis and Bishop have been a relentless duo over the tunnel's sequencing in the $6.4b transport plan.
It's not the first time the pair have teamed up on Wellington transport issues. The city's bus fiasco provided the perfect opportunity to, rather rightfully, drag Greater Wellington Regional Council over the coals.
Bishop, MP for Hutt South, enjoys a good petition and has proved an ability to gain traction on issues, like the Melling Interchange.
Willis has positioned herself as a go-to voice on the Wellington issues that stick, like Victoria University's controversial name change.
There's not a clear seat for Willis in the region but the tunnel presents an opportunity to bolster the party vote next year.
The tunnel issue transcends electorate boundaries because it's on the route to the airport, it's a bottleneck to get to kids' weekend sport, it's a symbol of a city that hasn't seen significant investment in its transport infrastructure in decades.
The Government has included the tunnel in the LGWM package, but it has been put on the back burner and National makes the argument that Wellington can't wait that long.
The secret letter saga ended in revelations Genter had in fact asked for mass rapid transit to be prioritised ahead of a second tunnel in exchange for her support.
LGWM is the child of a coalition Government and it's a transport package that Government won't want to unpick.
Twyford has said the fundamentals are not up for renegotiation and maintains congestion busting solutions are the priority.
He has being very careful with his words, especially with the election of Foster. In statements he has always maintained he's happy to sit down and discuss LGWM.
But let's not forget how he ended the statement he gave after Foster was first elected - "It [LGWM] was supported unanimously by all the councils in the region including by Andy Foster who voted for it".
With that in mind, Foster didn't go in all guns blazing when he met with Twyford and new Greater Wellington Regional Council chair Daran Ponter two weeks ago.
It's the beginning of a new relationship and irritating the minister on day one isn't exactly going to do him any favours.
Foster campaigned on bringing the second tunnel forward but now that he's in the city's top job he doesn't have much to go on, especially with a left lean around his council table.
He could now be counting on National to put the pressure on as the Opposition.
In an interview with Newstalk ZB's Heather du Plessis Allan he said most people in Wellington wanted a second tunnel and they should let that be known at the 2020 election.
Bishop and Willis won't want to let the tunnel issue die over summer, rather they'd like it to be a topic of conversation at summer barbecues.
They'll hope the campaign announced today will achieve just that.