Minister for Environment Dick Roche has refused a request from Friends of the Irish Environment to ban the use of balloons at public functions.
The lobby group had objected to the use of balloons in the recent commemoration ceremony for victims of the Air India disaster in Cork.
Spokesman Tony Lowes wrote to President Mary McAleese, explaining that the group was "greatly disturbed" to hear of her participation in the event, which included "the release of balloons to the environment".
The concern centres around the remains of airborne balloons blown out to sea, where they can be lethal to sea turtles, dolphins, whales and other fish, and to seabirds who mistake them for jellyfish, their natural prey.
"Balloons exposed floating in seawater deteriorate much slower than those exposed in air, and even after 12 months of exposure still retain their elasticity, with potential lethal consequences for marine life," said Mr Lowes.
Mass releases of balloons are illegal in some American states including Connecticut, Florida, Tennessee, California and Virginia, and similar legislation is pending in Massachusetts, Maryland and New York.
In Britain, the Marine Conservation Society is campaigning to educate people about the dangers of releasing balloons.
The group is asking corporate and government event planners to sign on to its voluntary ban on the practice.
However, while he acknowledged there have been reports of marine animals found with balloons in their stomachs, Mr Roche rejected the society's call for a ban.
In a written reply to Green Party leader Trevor Sargent, Mr Roche said he was aware that balloons, partially inflated, had been found accumulating on islands off the east coast of Canada.
But he said he was also advised that 90 to 95 per cent of balloons rise to an altitude of five miles, where the temperature and pressure is such that the balloons burst into small fragments, with no potential to harm marine animals.
A letter written on behalf of Mrs McAleese said the "views on the use of balloons for the ceremony had been noted".
