The Bay of Plenty Regional Council is on the look out for people illegally and repeatedly dumping animal carcasses into a Tauranga river.
It says three mutilated deer carcasses have been found dumped under a bridge in the Wairoa River, just upstream from a popular whitebaiting area.
Last month, two-and-a-half tonnes of rubbish - including sheep carcasses, guts, and heads, as well as tyres, batteries, computers and engines - was pulled from a 200 metre stretch of the same river.
The council's pollution prevention leader, Annabelle Ellis, says she doesn't know whether the incidents are related.
She says police have been alerted and the council wants anyone with information to report it to police.