Councillors decided during a closed-door session this week to look into ORC actions surrounding the March incident.
About 250cum of demolition material was placed on the river bed near Balclutha by Andrew Haulage on March 9.
An Environmental Protection Authority (EPA) investigation was launched, and when it publicly emerged that the construction company had been told by an ORC staff member that it could dump material into the river, it was labelled "extraordinarily embarrassing" by Cr Michael Laws in July.
Cr Laws went on to say he was concerned councillors were only informed of the ORC’s role after it was obvious the Otago Daily Times was going to write a story about it.
Those statements in part led to a code of conduct complaint against him by the ORC’s chief executive.
He was cleared of any breach last month.
But now, nine months after the incident, ORC chairman Andrew Noone said retired High Court Judge Sir Graham Pankhurst QC would be approached to carry out an inquiry into the incident.
Mr Noone declined to comment further yesterday.
But in a statement he issued after the closed-door meeting, he said the terms of reference for the inquiry were not complete but two major issues that remained for councillors were why the demolition material sat untouched in the river for three months before it was removed and how the processes of the ORC could be improved to better meet its environmental responsibilities.
Councillors had committed to publicise the outcome of the inquiry "in accordance with the council’s objectives of honesty and transparency", he said.
In a separate statement issued at the same time as Mr Noone’s, ORC chief executive Sarah Gardner said the inquiry would be "process focused" and would look at lessons learned.
The responsibilities for an employment investigation sat with her and not the councillors, she said.
She respected the decision the councillors had made and would assist the inquiry, "consistent with legal obligations", she said.
Yesterday Cr Laws said around New Zealand there was a debate at the moment about where governance stopped and management started and vice versa.
He was proud of the councillors’ decision this week, he said.
It was a fundamental part of elected members’ roles to ensure they tested operational effectiveness and efficiency and ensured councils were doing the right thing, Cr Laws said.
"You don’t have inquiries if you think everything is all right."
Otago Fish & Game first called for the dumping to be investigated in March.
Yesterday, Otago Fish & Game chief executive Ian Hadland said another inquiry seemed to be an unnecessary waste of resources.
The ORC deserved credit for getting the EPA to investigate as a third party in the first investigation and he was satisfied that had been thorough.
"We have been reassured that lessons were learned [by the ORC] and they made changes internally to stop this happening again.
"I thought that was the end of it."
