She said the council will review what type of action needs to be taken in relation to the incident.
Brunton said earlier that finding livestock dumped in rivers was relatively rare.
"These incidents across the region are rare but we regularly remove butchered remains of animal carcasses - mainly deer - from the Tutaekurī River access reserves, near Puketapu.
"Carcasses have been dumped in the Tūtaekurī River access reserve around 15-20 times this year."
Local Jo Worsley found sheep carcasses dumped by the Karamu stream, Chesterhope, Hastings.
Worsley said the dumping was "disgusting".
"We go down to this particular spot to go whitebaiting every year and we had just gone down to let the dogs have a bit of a run. We couldn't even let them out of the car once we saw that."
She suspected that the carcasses had been dumped there during the daylight because she found them in the afternoon and the area was out of sight from the road.
"We've seen seafood shells, all sorts of things dumped in the creek. Obviously a little dumping ground, but that was the worst that I've seen I'd have to say."
"It's the only time we've seen livestock. It didn't smell a lot, so I am assuming it was pretty fresh."
Brunton said earlier animal remains were a pollution concern because they cause a significant increase in E.coli in the waterway, particularly given the water is slow moving in the case of Ngaruroro River.
"It will deprive the water of oxygen as it breaks down and becomes a fertiliser to the water body, increasing the weed growth in the water impacting on the aquatic life in the stream."
She said a fine of $750 can be applied if carcass dumping occurs near a waterway.
"If the issue was deemed substantial, in the public interest or a repeat then the offender could face prosecution in the Environment Court and face a penalty of up to two years imprisonment or a fine up to $300,000."
Anyone with any information on the incident is encouraged to contact the Hawke's Bay Regional Council Pollution hotline on 0800 108 838.
