National Party MPs want construction of Wellington's proposed extra Mt Victoria tunnel to be brought forward.

Wellington City councillor Sean Rush has implored his colleagues to help "trapped" people in the eastern suburbs by advancing the case for an extra Mt Victoria tunnel.

Rush made the comments at a city council meeting on Wednesday, in which councillors endorsed funding for the next two years of the 20-year Let's Get Wellington Moving (LGWM) programme.

The council will spend $18 million for its share of early projects such as reducing central city speed limits, increasing bus priority, building cycleways, and funding initial business case work for a mass transit system, an extra Mt Victoria tunnel, and roading improvements at the Basin Reserve.

KEVIN STENT/STUFF An extra tunnel, projected to cost $700 million, would be built adjacent to the existing tunnel State Highway 1 tunnel. (File photo)

Rush, an Eastern Ward councillor, tried to pass an amendment calling for council staff to report back on any early opportunities found by the LGWM team to speed up the tunnel project.

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The amendment failed, mainly because a recommendation was already on the table for councillors to receive monthly briefings on how work was progressing.

SUPPLIED Wellington City councillor Sean Rush has begged his colleagues to help him bring forward the proposed Mt Victoria tunnel project. (File photo)

But the suggestion caused considerable debate among councillors, with Rush eventually issuing a plea.

"Please, we are trapped," he said.

"We're in an island. We've got one supply route [to the central city], and there are more people coming to the east in our urban development plan and the airport plan to double its foot traffic."

KEVIN STENT/STUFF A duplicate tunnel is not scheduled to be built until after 2029. (File photo)

But others disagreed, saying any intention to push the case for an extra tunnel was jumping the gun.

Fleur Fitzsimons said Rush was trying to second guess the outcome of business cases, while Deputy Mayor Sarah Free said although eastern suburbs residents "really want a tunnel", bringing the project forward was not the answer.

Jill Day said congestion was worse at different times of the day, "which suggests to me that the solution is not necessarily another tunnel".

KEVIN STENT/STUFF Councillor Iona Pannett says she does not put a lot of weight on business cases. (File photo)

"I think it's a short-term decision that's politically popular, and that does often drive people when they're making decisions, but we really need to think about what's the right decision."

Iona Pannett said she would not be convinced of the case for an extra tunnel regardless of what the business case showed.

"I do not put a lot of weight on the business cases, with the greatest deal of respect. It depends who does them, first of all, and it depends on which philosophical basis that you choose to act."

KEVIN STENT/STUFF Mayor Andy Foster says the business cases cannot simply be ignored. (File photo)

Mayor Andy Foster said business cases could not be ignored.

"Iona, if you don't believe in the business cases, then you should vote against the paper as a whole because a large chunk of the investment there is about the business cases.

"If we don't have confidence in the business cases, then we are just simply going to say, 'What is my predilection? Let's make a decision now'."

LGWM is a joint venture between the city council, Greater Wellington Regional Council and the New Zealand Transport Agency.

Over the next two years, the agencies will spend a total amount of $34.1m on early works, and $46.4m on early business case work.

The city council will commit $14.1m, with much of it to be funded through debt and paid off over the next decade.