An alternate three waters plan has been proposed by the mayors of Auckland and Christchurch, with control and ownership remaining with local councils, and the type and degree of iwi involvement decided locally.

Auckland's Wayne Brown and Christchurch's Phil Mauger announced their plan today, and said the government's controversial plan did not have solid support in Parliament or with New Zealand's local councils.

The alternative two-page plan was co-issued with Waimakariri mayor Dan Gordon, and the three said they hoped other mayors, local councils, Local Government NZ and central government would look at it.

Under their plan, control and ownership of three waters would remain with local councils as it is now, but the government's new national water regulator Taumata Arowai, which was established in March, would be retained.

Read the document: Wayne Brown and Phil Mauger's Three Waters Management Plan proposal

"Regional Water Organisations ... would be unable to be sold outside local authority ownership [and] would have access to investment capital through a new Water Infrastructure Fund administered by central government's own Crown Infrastructure Partners," the statement from the three mayors said.

The trio said the plan allowed for "meaningful roles for mana whenua" when it came to Three Waters, and decisions about whether co-governance would be established between councils and iwi would be decided by each community.

Wayne BrownWayne Brown is the new mayor of Auckland Photo: RNZ / Lucy Xia

They also want an "Vulnerable Water Schemes" programme set up.

"The most vulnerable schemes are those run by smaller entities, often in remote locations. It is difficult for these schemes to benefit from the economies of scale," the plan document said.

"We recommend that future additional capital investment is targeted at the most at-risk systems ... largely smaller systems in dispersed geographic locations. ...This acts like the Waka Kotahi Financial Assistance Rate for roading."

Phil MaugerPhil Mauger is the new mayor of Christchurch Photo: RNZ / Nate McKinnon

The government proposed greater centralisation of three waters - the delivery of drinking water, wastewater and stormwater - throughout the country following a series of incidents and reports showing some New Zealanders had to rely on sometimes unsafe, unreliable or unsatisfactory standards of Three Waters infrastructure.

The three mayors said those past problems were not likely to continue.

"The fundamentally most important part of the reform was better regulation of water. That has already been achieved with the creation of Taumata Arowai and heightened water quality standards that regional and unitary councils must achieve," they said.

They three also threw doubt on government suggestions that local councils would have to raise local rates if they kept ownership of their three waters programmes.

"In New Zealand, efficient water management will require strong local control and accountability, efficient finance and good management. Good local knowledge of the water catchment is also important in knowing what can deliver the best results. In practice that will deliver better results."

Reactions to the government's three waters proposals had been "ugly and angry", the three mayors said, and they believed this plan could lead to unity.

"The three waters debate has become divisive and lost sight of the key ambitions for better water in New Zealand," the statement said.

"The debate has been fierce, but some common ground has been found ... we believe we can find a consensus plan that we all support to deliver New Zealanders safe and reliable drinking water and wastewater services."

Minister of Local Government Nanaia Mahuta said both mayors had realised the status quo was "untenable".

She was happy they had signalled that they wanted to start a dialogue on the issue.

"We will consider certainly matters that they have raised, some of the areas we've traversed already but the most important thing is that the dialogue on this particular challenge remains open," Mahuta said.

Mahuta said the reforms were at an important juncture as the select committee heard the recommendations and submissions of various groups on the proposed legislation.

"Where there are improvements to the legislation to improve the workability of the legislation and be responsive in key areas that don't upset the overall balance of the objectives for water reforms, we are very open to receiving those recommendations and we look forward to their report."

Ardern said the government was open to changes to the three waters that improved the existing plans, as long as they did not move away from the fundamentals of them.

"We're at a junction now where we've been receiving public feedback and of course we've said we're open to making refinements and changes that improve the reforms here that are just so necessary, but our bottom line here is we don't want to change those matters that are focused on keeping cost of living in check," she said.

She refused to specify the fundamental matters of the reforms that the government would not budge on, saying she would prefer to negotiate through direct dialogue with the mayors.

"We are open to making changes that improve the proposals but we say that with a complete and utter focus on making sure that those changes don't undermine the fundamental principle which is making sure we don't see an increase in cost for ratepayers beyond what is currently projected which for many areas is dire."

Ardern said the mayors' proposal was made in "good faith" as both central and local government shared the priority of ensuring ratepayers did not experience a water bill price hike.

She said the three waters legislation remained on course to pass its third reading before next year's election.

Republished by arrangement