It yesterday called for an investigation and if warranted "appropriate compliance action" after the Otago Daily Times reported a Balclutha man saw a truck dump rubble down the riverbank behind the Balclutha Aerodrome this week.
The act could be a breach of Otago Regional Council water plan regulations.
Otago Fish & Game officer Bruce Quirey called the alleged dumping irresponsible and a sad indictment of the way some fragile river systems were treated.
The waste material left behind included breeze blocks, rebar, plasterwork, metal components and plastic piping, much of which would be pushed down the river in the next flood, Mr Quirey said.
The waste needed to be removed as a matter of urgency and disposed of in a responsible manner, he said.
The Clutha River was a critical environment, not only for sports fish and game birds but native fish, eels, birds, aquatic invertebrates, and plant life, he said.
A regional council community information session in Balclutha about Lower Clutha flood protection works was scheduled for later this month and he encouraged members of the public to attend.
The regional council previously noted it received a call to its pollution hotline, which it was "looking into".
Yesterday, a council spokesman said the council had nothing to add.
The company identified by the informant earlier declined to comment on the allegations.
