The Prime Minister's chief scientist has failed to address the real problems in his new water quality report, agribusiness consultant Alison Dewes says.
The report by the Prime Minister's chief scientist, Sir Peter Gluckman, said that while some waterways were in a good state, others had been significantly compromised by agricultural intensification, urban expansion and industrial pollution. Hydroelectric development and droughts also had an effect.
Ms Dewes said the report was a good start, but fell short of addressing the real water-quality problems.
"It's great coming out and admitting we've got a problem, it's a nicely presented report and follows on nicely from the OECD report and admits things, but I do have some concerns.
"There's lots of elephants in the room. There's not really any talk about cows or recent conversions of vulnerable landscape at extensive levels."
Ms Dewes said there was plenty of conversation around riparian planting and fencing waterways, but it did not go far enough.
"Riparian planting is only part of the solution, it (the report) doesn't seem to want to understand or acknowledge that contaminants - nitrogen, phosphorous, pathogens - actually travel through soils, not just over them."
Water allocation also needed more attention, Ms Dewes said.
"There is a lot of focus on municipal, hydro and industrial water use, but 78 percent of New Zealand's water, excluding hydro, is used for irrigation of pastoral agriculture."
Ms Dewes said land use should be put under the microscope.
"In some cases we are going to have to see a reverse of the way we are using our land.
"It's the last 25 years that we've really tipped the balance ... we've used 400 percent more nitrogen fertiliser, we've imported two million tonnes of palm kernel, we've irrigated another 400,000-odd hectares on gravely soils - this is the stuff that is the real problem, how are we going to deal with it?"
Federated Farmers backing the report
Federated Farmers water spokesperson Chris Allen said farmers were well aware of the issues.
"We've acknowledged for a long time that yes, we [farmers] do have an effect on water quality in some places and we've stepped up to the mark to make sure that we are taking those steps that we need to where there is water quality problems, and make sure that we are doing good farming practices.
"The report's saying a lot of the stuff that Federated Farmers have been saying for a long time. That we're all got our part to play in water quality, all aspects of society, whether it's farming, tourism or urban, we've all got our part to play and we're all part of the solution."
Environment Minister Nick Smith said the government was moving on the issue, banning further agricultural intensification in 16 catchments and investing $450 million into fresh water clean-ups.