Extending mass rapid transit to one of Wellington's biggest suburbs is being campaigned on in this year's local body elections.
Estimated capital cost for mass transit in the Let's Get Wellington Moving project is $2.2b.
It's the big winner in the $6.4b transport overhaul but exactly what technology will run along the route is yet to be decided.
Last week mayor Justin Lester told Wellington business leaders he was personally in favour of trackless trams.
"I think they hold enormous potential and if that technology works, which is yet unproven, but if it does, I think it would be hugely beneficial."
Trackless trams would be a cheaper option to put on the route than light rail.
Lester said if there was money left over for the public transport mass transit component of LGWM, he'd look to extend it to other parts of the city, with Karori being the first priority followed by Island Bay.
Labour candidate for the Onslow-Western ward Rebecca Matthews has jumped on that idea turning it into a campaign platform, saying trackless trams could be in Karori by 2022.
"The thing about trackless trams is obviously you don't need to lay tracks, they just go on the road. So once you dedicate the road space, it's very easy to install them", Matthews said.
Karori has undoubtedly been hit hard by last year's disaster new bus network rollout, with the fallout continuing to this day.
"The bustastrophe has had a massive impact on Karori and it's forcing people back into their cars.
"It's such a big suburb, there's so many people, and currently they're so underserved by the bus system, it's completely unreliable, it's inconvenient. So, I do think it should be a priority area for Let's Get Wellington Moving," Matthews said.
One problem with getting a dedicated mass transit route into Karori is the suburb's tunnel, which has one lane in and one lane out.
The Government has been clear it's not keen on tunnel building, putting a second Mt Victoria tunnel on the back burner and not funding a second Terrace tunnel at all.
So it seems more likely that while mass transit would have priority everywhere else on any transport spine to Karori, it would have to compete with cars at the tunnel.
Karori's tunnel already comes with its own issues.
Wellington City Council work to make it safer, more accessible for pedestrians and to stop it from leaking has been put on hold.
The tender WCC received exceeded its budget for the work.
The tunnel was built in 1900 and is Wellington's oldest road tunnel. About 114,000 vehicles now pass through it each week.
What to do about the tunnel in the context of mass transit was one of the details that would need to be worked through, Matthews said.