Birdwatch Ireland is "alarmed" at emergency orders that could be utilised by the Government to override planning procedures for a no-deal Brexit scenario at Dublin and Rosslare ports.
The group is concerned for the safety of birds who make their habitats within Ireland, including a colony of terns in a special protection zone at Dublin Bay.
The Government is set to rely on emergency planning orders in the wake of any no-deal Brexit on March 29.
Oonagh Duggan, assistant head of policy and advocacy at Birdwatch Ireland, said: "We are living in an ecological emergency, with 68pc of regularly occurring birds in Ireland on the red and amber lists of the Birds of Conservation Concern in Ireland. Any shortcuts on environmental assessment could have devastating consequences on wildlife."