National is promising to repeal the Government's three waters reforms and return water assets to councils if it wins the next election.
Local Government Minister Nanaia Mahuta is currently weighing up feedback from councils on her three waters proposals, which would see each council give its water assets like pipes and reservoirs into one of four massive new water entities.
These four water entities will manage all water services in New Zealand, including freshwater, stormwater, and wastewater, collectively known as "three waters".
Councils will collectively own the new water entity their assets are rolled into, but they will have almost no control over it.
This has stirred no small amount of controversy in councils, and led to a breakdown in the relationship between some councils and the Government.
The Government now refuses to rule out forcing councils to part with their water assets, despite previously saying the water reforms would effectively be voluntary.
National leader Judith Collins said she would repeal any changes and "return any seized water assets back to councils".
"Labour's proposal to centralise council water assets into four mega-entities, taking them away from local ratepayer control, is hugely unpopular with a majority of councils across New Zealand," Collins said.
"It's clear the Government plans to imminently legislate their Three Waters Reforms and make them compulsory for all councils, forcibly seizing ratepayer-owned water assets and bundling them into these new entities," she said.
Collins said she would "unwind" the changes if she won the election in 2023.
"The next National government will also return any seized water assets back to councils," Collins said.
"Labour needs to urgently halt their Three Waters plans, and abandon their appetite for amalgamation."