A BOARD member with An Taisce has branded the outcome of a departmental review of planning malpractice allegations as "bizarre".
The heritage body had accused Dublin City Council of "serious impropriety" by "encouraging" landowners to lodge planning applications which breached the city development plan.
The Department of the Environment said there was no evidence officials acted improperly.
But An Taisce's James Nix said the report published by Housing Minister Jan O'Sullivan is "extraordinarily curious".
"She (Ms O'Sullivan) outlines that the material disclosed (by An Taisce) reveals between serious and very serious allegations but then at the same time full square, wholeheartedly acknowledges that there was no investigation carried out (by the Department of the Environment)," he said.
"So how then you can draw conclusions based on the fact that you just admitted you didn't even investigate absolutely baffles me. It's an extraordinarily bizarre and curious turn of events."
Mr Nix, a former Green Party election candidate, made the comments at a meeting of the city council's economic and planning committee.
He was interrupted by Fine Gael councillor Ruairi McGinley who told him not to make such comments about the minister.
"The minister is democratically elected and you better have some respect for her," Mr McGinley said.
Ms O'Sullivan this week published a review which examined complaints against seven local authorities.
She said no evidence of criminality or corruption was uncovered but weaknesses in the implementation of planning law and poor administration were found.
The complaints by An Taisce about Dublin City Council concerned decisions to grant planning permission to substantial developments that were subsequently overturned by An Bord Pleanala.
The Department of the Environment report said there was no evidence to support the allegations.