He also supported the Greens' call for a ban to be put in place for any future dairy farm conversions till such time they could achieve best practice sustainable farming.
He said the Northland Regional Council needed to put a policy in place to have enforcement legislation that served abatements and fines for effluent discharge and unfenced cattle on our waterways.
"We need monitor patrols that are as vigorous as our parking and noise control wardens are, and that they have the equipment and law behind them to do the job. To say that we should have a particular swimmable river at one place but not this other one sends a message that we can still pollute them, and the decisions would be industry-driven," he said.
Greens' co-leader Metiria Turei launched the campaign last week at the party's annual meeting in Lincoln, Christchurch. "Our rivers don't need to continue their decline. That's why we need to change the government," she said.
The Government has introduced bottom lines for freshwater quality which require rivers to be clean enough to wade in - a threshold the Greens say is too low.
Environment Minister Nick Smith says it is not practical to improve all water quality to a "swimmable" standard.
The Government has also set deadlines for livestock to be fenced off from rivers and streams. In last week's Budget, it set aside $100 million for cleaning up waterways over 10 years - an amount Mrs Turei said was not enough.
A policy to clean up New Zealand's rivers was at the heart of the Greens' 2011 election campaign.