An Taisce has called on the Minister for Communications, Marine and Natural Resources, Mr Ahern, to publish a major report on Dublin Port's plans to extend into the bay.
"The decision by the Department of the Marine to hold back on a review that was carried out by independent consultants into the port company's environmental impact statement is, mildly put, remarkable", An Taisce said.
Last week, the Department of the Marine announced it was shelving another study that was meant to assess the needs and impact of future development in Dublin Bay.
The announcement came as the port was planning a further 52-acre infill.
"To abandon one study is short-sighted, but to refrain from releasing another would appear most questionable", said a spokesman for An Taisce.
Referring to last week's report by the Environmental Protection Agency on the quality of bathing waters, the spokesman said it was encouraging Sandymount and Merrion strands now appeared to fulfil the mandatory criteria.
It was a major concern that only five of Dublin's 14 beaches met the higher guideline standards under the EU Bathing Water Quality Directive.
An Taisce cautioned Dubliners "intent on taking a pollutant-free dip" to avoid the beaches at Brittas Bay, Co Wicklow as they "failed even to fulfil the most basic criteria" of the mandatory EU standards.
The most positive result from the latest survey was that "for the first time in years, the quality of freshwater inland bathing areas achieved a 100 per cent compliance rate with both the EU mandatory and guide standards".