The Government is to contribute $5.2 million towards a clean-up of the Manawatu River.
It's part of an $8 million package announced by the Prime Minister at a conference in Auckland.
Other waterways to benefit will be lakes in Wairarapa and the Wainono and Waituna lagoons.
The funds are part of a $15 million package announced last year.
The $5.2 million grant is about 17% of the costs to clean up the Manawatu River.
The pollution in the Manawatu River is the result of decades of farming runoff, wastewater discharge, industrial waste and treated sewage.
The $5.2 million will be spent over the next two years on fencing off more than 200 kilometres of the river, and on upgrading sewerage treatment plants in the region.
In 2009 research from the Nelson-based Cawthron Institute found the river had the highest reading of depleted oxygen of 300 rivers and streams in North America, Europe, Australia and New Zealand.
Last year, a spat between the Palmerston North City Council and the regional council broke out over the river, and the matter is likely to head to the Environment Court.
Environment Minister Nick Smith is confident the dispute won't get in the way of the clean-up.
He says the two councils have been constructively engaging around resolving those issues.
"So no we wouldn't be putting the money in if we thought there was not the genuine commitment from both the city council and the regional council to resolve those issues, I'm satisfied of that", Dr Smith says.
Manawatu Whanganui Regional Council chief executive Michael McCartney says the grant is a huge help towards the arduous restoration task.