The Ministry for Culture and Heritage acted unreasonably in its public consultation for a memorial to the Mt Erebus disaster, says the Chief Ombudsman.
In a report released on Monday, Judge Peter Boshier said Manatū Taonga should have consulted more widely before forming its preference for a location.
He also found the ministry acted unreasonably in October 2019, when it failed to reply to correspondence about resource consent for the proposed memorial.
The memorial, planned for Dove Myer-Robinson park in Parnell, will commemorate the 237 passengers who died when an Air New Zealand flight crashed into Antarctica's Mt Erebus in 1979.
It is planned for the site of the Parnell Rose Gardens, but it is opposed by some community and Māori groups who, among other reasons, fear for the health of a sacred pōhutukawa. It is these groups who brought the complaint to the Ombudsman.
"My view is that the ministry should have consulted the wider local community and all Tāmaki Makaurau iwi comprising the mana whenua before forming a preference for any site in Auckland," Boshier said.
"To not do so is surprising given the Crown's partnership obligations under Te Tiriti/Treaty of Waitangi and obligations at an international level to consult with indigenous peoples."
The site does have the endorsement of the mana whenua of Parnell, Ngāti Whātua Ōrākei.
Boshier also found that despite flaws, the ministry's preference for the site could not be said to be wrong, and that it did not act unreasonably in the design process.
However, he said consultation could - and should - have been more widespread.
"This lack of consultation has denied wider community and Māori involvement in considering a range of possible locations for the national memorial. Some members of the local community and iwi still have a sense of grievance over this failure," he said.
Boshier called for the ministry to resolve any grievances before construction begins.
In a statement, the ministry said officials are carefully considering the report and recommendations, though there's nothing in it to indicate the project can't continue.
"The Ombudsman has recommended that, before construction begins, the ministry takes reasonable steps to engage with opponents of the memorial to attempt to resolve their sense of grievance," chief executive Bernadette Cavanagh said in a statement.
"Ministry officials have already commenced dialogue with the opponents of the memorial."
Cavanagh said she was confident that correct and proper processed had been followed to select the site, and that environmental, cultural and heritage values have been respected and protected.
"While the process the ministry undertook followed practice established over decades, we appreciate the Ombudsman's comments and will take these into account in the future," she said.