Environment Minister Dr Nick Smith is defending the Government's track record on cleaning up New Zealand's rivers, saying it's done more to improve water quality than any previous government.
It comes after the Green Party launched a major new environmental campaign at its annual conference in Christchurch over the weekend targeting 10 of the country's dirtiest rivers, including the Waikato, Tukituki and Manawatu rivers.
Greens' co-leader Metiria Turei wants to make the rivers safe to swim in and MPs will be hitting the road to highlight what's threatening the waterways - including over-intensification of dairying, sewerage and industrial pollution - and what can be done to clean them up and protect them.
"Rivers can be clean enough to swim in, but only if the Government lifts its 'wadeable' standards and demands they be 'swimmable' instead," Ms Turei said.
"Under National nearly two-thirds of our rivers are unsafe for swimming. New Zealand needs a government to back our rivers and to stop defending polluters."
But Dr Smith said it is ill-informed of the Greens to blame the current government for the country's water quality issues.
"All the science shows these issues go back many decades," he said.
"Many of our rivers and lakes have nutrient run-off cycles of many decades and it will take a similar period for the limits National has put in the place, and the clean-ups, to deliver the required improvements in river quality."
As well as ramping up investment in clean-up projects, Dr Smith also pointed to consultation the Government has under way on new national rules on fencing to keep stock out rivers and lakes and on tighter new standards, including "swimmability".
"Our government has done more than any in our history to improve water quality of our lakes and rivers," he said.
"We welcome the Greens renewed interest in fresh water quality issues. It is one of the government's top environmental priorities."