Greenpeace activists are due to arrive in Dublin this week to prepare for a protest against a shipment of radioactive waste which will travel through the Irish Sea to Sellafield.
Their ship, the Rainbow Warrior, is set to dock in Dublin from where campaigners will plan their campaign.
The material is being sent back from Japan after the authorities there refused to accept it from the Cumbrian nuclear waste processing plant.
A spokesman for British Nuclear Fuels Ltd (BNFL) insisted the consignment was not weapons grade material. "People would find it almost impossible to separate the material out to make any form of nuclear device," he said.
Greenpeace has vowed a peaceful protest and the Rainbow Warriorwill be among a flotilla expected to greet the two heavily armed cargo vessels when they arrive in the middle of next month.
Campaigners are set to brief journalists about their protest plans on Wednesday and may also launch a flotilla to demonstrate on September 1st.
The Labour Party marine spokesman, Mr Eamon Gilmore, has called on the Minister for the Marine, Mr Dermot Ahern to "use every international convention on marine safety to prevent this shipment from travelling through the Irish Sea".
"The Minister must assert Ireland's rights to protect its citizens from dangerous shipments in neighbouring waters, and prevent this shipment, which contains enough material to make up to 50 nuclear weapons," he said.