The "iconic" Hundertwasser Art Centre project has been hit by a budget blowout - construction costs of $26m have ballooned by $4m.
The shortfall has been put down to law changes requiring higher safety standards, the discovery of unidentified asbestos and technical difficulties encountered during construction of the distinctive building.
Whangārei mayor Sheryl Mai has told the Advocate no ratepayer money will be used to plug the gap and has reserved council's right to carry out a review on the project's finances.
Those opposed to the project from the start say the issues are no surprise and should have been identified from the outset.
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Construction of the Hundertwasser Art Centre and Wairau Māori Art Gallery started 14 months ago with the centre due to open in July next year.
The building was first mooted in 1993 after a design was put forward by Austrian artist and architect Friedensreich Hundertwasser.
It was embraced and rejected on a number of occasions until a public referendum in 2015 saw more than half the voters support its creation.
Newly-appointed Whangārei Art Museum chief executive Kathleen Drumm said the cash shortfall had been identified eight weeks ago and efforts were under way to raise the extra money needed.
"I can't say it's going to be easy but I'm confident we are going to find it."
The foundations had been planned for 25 metres - they are now at 37m - and the former Northland Harbour Board revealed "previously unidentified asbestos". Design issues included "concrete pourers … struggling to get concrete around bent steel".
"We're not apportioning blame. It is what it is. It's come about through unfortunate circumstances so now let's fix it through savings and sourcing additional funding.
"There's a lot of savings being made and a real confidence we are going to manage this."
Drumm, who only recently started, acknowledged the controversy over the project. "One of the things that attracted me to the project is there was a community arguing about art."
She said she was confident the original vision would be met. "It will be a unique building. It will be iconic."
The shortfall will draw greater focus to the role of council, with the controlling Whangārei Art Museum Trust Board a council-controlled organisation.
Mai said she had been briefed, along with councillors, over the budget gap. "We are confident they will find the funds."
She said the money would not come from ratepayers and there had been no request from the trust board for assistance.
Mai said council could seek to review the finances for the project. "If council feel we need that level of comfort, that is something we could do."
The budget gap has been met with resignation by those who opposed the project.
Councillor Tricia Cutforth said those familiar with the harbour and the former harbour board building would have no surprise over foundations needing extra depth and extra asbestos.
"I'm worried and I'm very sad but I'm not surprised. I think the new chief executive has walked into a huge challenge and not one of her making."
Cutforth said the project was never meant to rely on public funding and it had already cost ratepayers $2.5m. She said there was also a cost in staff time and other public resources.
She said trust board's status as a council-controlled organisation meant the final responsibility rested with council.
"We definitely have a role overseeing and examining the finances."