Evidence showing cattle getting into rivers and anecdotal stories of animals being slaughtered next to streams have renewed calls for the introduction of a bylaw to exclude stock from Hawke's Bay's waterways.
It comes after vandals cut a fence to access their favourite river spot, also giving cattle a free pass to access and trample the banks as well as defecate in the water upstream from swimmers and fishers.
A Napier angler, who did not want to be named, spotted more than 20 cattle in the Tutaekuri River, near Brookfields Bridge, between Meeanee and Pakowhai this week.
"The reason it concerned me is that people are further down swimming and fishing while the cattle are in the same river and we're being told by the regional council not to let any cattle into the waterways.
"I used to fish a lot in that river and was driving past the other day, had a look over and saw the cattle standing in it. Obviously they are drinking because it's hot and they're able to do what they do in the water."
Regional council acting manager of compliance Wayne Wright said the council owned land at Brookfields Rd, next to the river.
"We have cattle there which we graze to keep the vegetation down. They are fenced off from the river.
"What is happening is that people want free access to the river and someone is cutting the fence down to get to the water, which is allowing the cattle in."
Mr Wright said it had been an ongoing problem. The regional council could prosecute the vandals as it was deemed "wilful damage".
The regional council currently had no rules which prohibited cattle from walking into rivers and streams but encouraged farmers to use "best practice" and not allow their animals near waterways.
"The only offence which may come from cattle in the river, could be if the water is contaminated, which basically needs to be proven by analysing the water."
Fishing club members reported hearing stories that people were also butchering cattle on the river banks as the animals were easy to access. It was thought up to 50 stock a year were lost to thieves but Napier Freshwater Anglers Club president Hugh Peterson said those stories could not be verified.
"I haven't heard anything substantial on that matter, it's only stories second or third hand."
Mr Peterson said cattle in rivers "were a nuisance" if they weren't fenced off property and caused "a hell of a mess" on side streams.
Angler Ian Fleming said the Brookfields Bridge area has a lot of visitors since the cycle and walking trails were put in nearby.
"You would have to be happy with the work the regional council is trying to do by grazing the river banks and fencing the cattle off ." Mr Fleming and Mr Peterson did not think it would be anglers cutting the fence as fishers wanted the best possible water quality.
Fish and Game New Zealand's Hawke's Bay regional manager Peter McIntosh said the regional council needed to set an example by continuing to fence off cattle.
"There is no bylaw to exclude stock from rivers but one is needed.
"That is something we will be pushing for, stock exclusion from rivers Hawke's Bay-wide. It keeps effluent out of the water, keeps sedimentation down because the banks crumble when the cattle get up and down and release a lot of phosphorous and nitrogen."
Mr McIntosh had not heard of any cattle butchered at the river but had fielded reports of sheep being slaughter and the guts of the animals thrown into the river.
"People think they are feeding the animals but it's not too pleasant when you see that go floating past when you're fishing or swimming."
Regional council chairman Fenton Wilson said using cattle to graze the edge of rivers was the most economical option to keep the stop banks in "pristine condition" for the public.
"Everyone in charge of livestock has an obligation to do the right thing to manage the integrity of the waterways. We encourage people to use our 24-hour hotline number if they have any issues."
The pollution hotline is 0800 108 838.