A Hawke's Bay Regional Councillor believes people are being mislead over the possible source of Havelock North's water contamination.

Preliminary DNA results show the campylobacter is from ruminants, such as sheep, cattle or deer.

The Hawke's Bay Regional Council has since released a statement saying the Tukituki River is a "very unlikely" cause, because river samples have come back at typical levels for water quality.

It also states that more importantly, no bores between Tukituki River and Havelock North have e-coli.

However, Regional Councillor Tom Belford said he's photographed cows grazing along the riverbanks on Tuesday, and another landowner saw at least 30 cows in the river itself this week.

Mr Belford said the river is not in the clear, and people don't need to look any further than the cows presently grazing in the river.

Earlier this week, the pollution of Havelock North's drinking water became a hot water issue in Parliament.

Green Party Co-Leader Metiria Turei is critical of the inquiry, announced by the Government, which won't cover land use, saying it's well known intensive agriculture is linked to declining water quality and therefore could be a factor in this outbreak.

But the Prime Minister said the inquiry's terms of reference are very broad.

John Key doesn't think that Turei should jump to conclusions about what the cause of the water concerns are.