Documents reveal just how frustrated and concerned Treasury was behind the scenes of Wellington's $6.4 billion transport plan.
An email leading up to the finalisation of the Cabinet paper for Let's Get Wellington Moving shows Treasury asked why a second Mt Victoria tunnel had been put on the backburner.
"Why is the Minister [Phil Twyford] proposing to build the second Mt Vic tunnel after rapid transit has been delivered? There is no explanation for this sequencing", April 18, 2019 email said.
The sequencing of projects is the subject of a secret letter Julie Anne Genter, Associate Transport Minister and Green MP, penned to Twyford just a few weeks before on March 26, 2019.
The refusal to publicly release it has heightened speculation over how much influence the Greens had over the transport project, in particular, the decision to push back construction of Wellington's second Mt Victoria tunnel.
"We have a number of concerns"
Treasury was also concerned the benefit of projects was largely unknown and that wasn't made clear in the paper.
"Given that the Minister is asking Cabinet to endorse a large and costly package of investments, we consider it important that Cabinet is aware that the benefits may not justify the costs."
The email criticised the paper for having little detail of what the package consisted of and for not explaining why the proposed investments would solve the city's problems.
It even took issue with the use of a word cloud graphic which it called "anecdotal and emotive, rather than conclusive evidence of a need for these particular investments".
The end of the email recommends Cabinet merely note the paper and should "certainly not" endorse it or agree for Twyford to make an announcement.
"However, we understand the Minister is unlikely to proceed on that basis", it said.
Twyford has previously said Cabinet decided to endorse the package because Wellingtonians had waited decades for transport investment.
He said officials had done a lot of work crunching the numbers, looking through cost implications, and he would report back to Cabinet with a long-term financing proposal in due course.
The secret letter
Wellington based National list MP Nicola Willis, who received the email in an Official Information Act response, said it was clear Genter was calling the shots and government advisers had been left in the dark.
"This document proves that as far as officials were concerned, there was no logic in the decision. It was all politics", she said.
Treasury was asking the same question everyone in the capital is - why delay the Mt Victoria tunnel project?, she said.
Willis believes the answer to that question lies in Genter's secret letter to Twyford.
Genter's refusal to release the letter is before the Chief Ombudsman who has formed a provisional opinion on the matter.
Roading projects, move over
Wellingtonians said they wanted to prioritise public transport, rapid transit and walking and cycling improvements, Twyford said.
"That's why we are going to deliver congestion-free options like rapid transit and public transport first so some people can leave the car at home, freeing up the roads for those who have to drive."
Twyford has received official advice that from a mode shift perspective, it is important for these things to be built ahead of road capacity.
This is so the door is left open to assess whether road capacity is still needed once alternatives are in place.
But the advice also said on some occasions it might be physically necessary to make a road investment to enable mass rapid transit.
The sequencing work undertaken for LGWM suggests construction on a second tunnel should start at the same time as rapid transit from the railway station to Newtown.
"The two state highway projects will be needed to mitigate the significant disruption that rapid transit construction and operation will have on the network south of the central city."