"We support the intent of the reforms but what they mean in practice is that Aucklanders would have imposed upon them a water services entity which has no democratic accountability to them through elected representatives," he said.
Auckland would be in a regional entity with Northland, and Goff said that would see Auckland contributing 94 per cent of the assets of the entity but would only get a minority voice on an oversight committee which would have little power.
He said Mahuta's rationale for the reforms was the poor quality of water services and underinvestment by councils but neither applied to Auckland, which had invested $11 billion in water services for the coming decade.
He said an overwhelming majority of councillors and all 21 of the local boards were opposed to it.
He said Auckland would work with the working group to improve the reforms, and wanted to ensure that the new water entities would retain their accountability and responsiveness to the people they serve through councils.
The Green Party has called for the controversial Three Waters reforms to be paused, while Act and National immediately pledged to repeal it, describing it as an "asset grab" and a blow for local democracy.
NZ First leader Winston Peters said it was "a blatant grab for unrestrained and unbridled political power" and accused Labour of announcing it under the cover of Covid-19 lockdowns.
"It represents a giant lurch towards a central government takeover of local government and ratepayers' assets."
However, Mahuta was unrepentant about the decision to force councils into the Three Waters Programme, saying it was needed after decades of underinvestment by councils in water.
The only concession to strong criticism of the plan by councils and the public was an agreement to set up a working group to reconsider the governance and accountability lines of the new entities.
Asked why the opt-in component for councils had been removed, Mahuta said the more they learned about the extent of the problem with the three waters network during the process, the more obvious it had become that change was needed.
"Two decades of under-investment in water infrastructure shows this a systemic, long-standing issue that hasn't been addressed.
"At the point at which we found just how dire the situation was we recognised, as did local government, that the case for change was compelling. The more we found out, the more we realised something had to change.
"It was evident that to ignore the state of the water infrastructure would be irresponsible."
Mahuta acknowledged there had been strong pushback on it, and that was why the new working group would be set up. That group would include local body, rural and iwi representatives.
Mahuta rejected the claim it was an attack on democracy, saying ratepayers needed and deserved good drinking water, infrastructure that could withstand weather events, and beaches without "no swim" notices on them - and delivering that was democracy.
Local Government NZ President Stuart Crosby said it was disappointing that the Government had chosen to make it mandatory for councils, but he was pleased it would reconsider the model by which it would operate. He urged councils to take part in that.
"While the announcement stings for councils who have been good stewards of their infrastructure, ultimately the nationwide affordability challenge in the water space needed to be answered."
The Green Party has also now called for the reforms to be paused – spokeswoman Eugenie Sage said there had not been enough time for communities to have their say and there would be scepticism about whether the Government's offer to reconsider the governance model was genuine.
Sage said the working group would only have seven weeks before legislation was put up on the reforms and that was not enough.
"Major reform like this needs to be done in partnership with iwi and local communities. The risk otherwise is a 'reverse Goldilocks' situation, where no one is happy with the outcome."
Mahuta acknowledged there were genuine concerns but also said some of the criticism of it was based on "mistruths and wrong information".
"That wasn't helpful."
Mahuta would not specify what that was, but there has been some criticism of the place of mana whenua working alongside councils in oversight under the model.
Under the proposal, the water assets of each regional entity would be collectively owned by the councils, while councils and iwi representatives of the regions would jointly be involved in decision making.
Winston Peters said that was part of a "covert objective of race-based co-governance without any mandate from the New Zealand people".
Mahuta dismissed that, saying it was an opportunity for iwi to be at decision-making table and exercise kaitiakitanga [guardianship] over water.
The decision to go ahead with the reforms was welcomed by Dr Te Maire Tau, co-chair of Te Kura Taka Pini, the Ngāi Tahu freshwater group.
She said as the tangata whenua of Te Waipounamu, Ngāi Tahu felt a responsibility to represent the interests of ratepayers and residents of the area and to make the reforms work for them.
Tau acknowledged that the reforms would mean change for councils and was not universally supported, but said there was general consensus that the status quo was not adequate for the people or the environment.
"Historical underinvestment and an 'out of sight, out of mind' approach to crucial infrastructure has led to mass illness, contamination, and literal eruptions of waste in the streets. It has also led to negative impacts on our rivers and streams, particularly in urban areas. These are issues that Ngāi Tahu and councils, and indeed all South Islanders, have a common desire to address."
Mahuta said the public would have a chance to have their say during the select committee process which would begin after legislation was put before Parliament in December.
Federated Farmers President Andrew Hoggard said the group opposed the changes and was concerned about their impact on rural services.
"This [working] group will have its work cut out to allay a multitude of concerns," Hoggard said.
"Top of the list for Federated Farmers are issues around governance and accountability. How will the new entities ensure the needs of smaller and rural communities are not crowded out when setting investment priorities and plans?"
