Julie Anne Genter has been ordered to issue a statement over her secret Let's Get Wellington Moving letter, but she has not been made to release the controversial note.
The Chief Ombudsman has ruled the Green MP and Associate Transport Minister was entitled to withhold a copy of the letter.
This was in order to maintain the effective conduct of public affairs through the free and frank expression of opinions between Ministers, and between Ministers and political parties.
"In my opinion, disclosure of the letter would discourage political parties and Ministers from expressing their views on draft policy papers in writing or as clearly and frankly as they might do in an environment of trust and confidence," Chief Ombudsman Peter Boshier said in his decision.
"It may also mean that consultation is delayed until a matter enters the Cabinet process where it can be discussed confidentially.
"In my opinion, these changes would adversely affect the efficient and effective development of Government policy in an MMP environment."
There's been months of speculation that the contents of the letter was the reason a second Mt Victoria tunnel was put on the back burner in the $6.4b transport plan.
Genter penned the letter to Transport Minister Phil Twyford on March 26 this year during pre-consultation on the LGWM indicative package draft Cabinet paper.
Twyford and Genter today released a statement ahead of the Chief Ombudsman making his finding public.
"Successive Governments have recognised discussions on Cabinet decisions need to take place in confidence to ensure the best decision is made," Twyford said.
"We supported releasing a statement to put to rest the false speculation whipped up by opposition MPs about the letter's contents," Genter said.
The pair have also clarified the nature of the letter after the Chief Ombudsman said doing so would promote public trust and confidence.
"The Associate Minister expressed views on the indicative package of investments outlined in the draft Cabinet paper. These regarded the alignment of the package with the goals of the Let's Get Wellington Moving programme and the Government's Policy Statement on Land Transport. The Associate Minister was concerned about inducing traffic and the resulting increased congestion, greenhouse gas emissions and undermining of demand for public transport. The Associate Minister was also concerned to ensure there was sufficient funding available for public transport.
"The Associate Minister advised that she was comfortable supporting this package if a number on matters were clarified, including that the public transport, and walking and cycling components of the package would be completed as soon as practicably possible and that work on rapid transit be prioritised ahead of the second Mount Victoria tunnel."
They said the letter did not issue any ultimatums nor threaten a resignation.
Boshier noted in his decision that by way of background, Genter said she held a meeting with Green Party co-leader James Shaw, Green Party spokesman for Wellington issues Gareth Hughes, a Green Party policy advisor, and her ministerial adviser on the morning of March 26.
They discussed the indicative package and as a result of that meeting Genter penned the letter.
The Associate Minister therefore considered the letter to be part of the political consultation process between the Green Party and the Minister of Transport.
But Genter acknowledged the letter could have been clearer that it reflected the view of the Green Party.
"Nonetheless, in the context in which the letter was sent it was assumed that it would be clear to the recipient that this letter reflected both the views of Julie Anne Genter and other Green MPs", she said.
The Ombudsman agreed the capacities in which Genter was acting in were not easy to separate and accepted the letter also represented the view of the Green Party as part of the political consultation process.
He noted that when the issue landed in the House for days on end things became confused.
Genter said in the House she wrote the letter in her capacity as a Green Party transport spokesperson, but subsequently confirmed she wrote it on Ministerial letterhead and signed by her as the Associate Minister.
The decision said Genter also made comments regarding the concerns she expressed in the letter and by way of this disclosure, "partially waived the confidentiality which would otherwise have attached to this pre-consultation communication".
Her concerns were also somewhat vague saying little more than they related to the "sequencing of projects".
"The statements in the House generated significant public and parliamentary debate, as well as confusion, public disquiet and speculation.
"In these circumstances, there are considerations favouring disclosure in the public interest that outweigh the need to withhold some information about this letter. In my opinion, a clarifying statement is required to inform public understanding about the matter and promote public trust and confidence," Boshier said.