The Department of the Environment has moved to reassure the public that two ships transporting weapons-grade plutonium past the south coast today will not enter Irish waters.
A spokesman said that while the coastguard and the Aer Corps were monitoring the situation, the Government had received assurances that the vessels will remain in international waters.
The vessels are carrying more than 300 pounds of plutonium from US nuclear warheads.
Green Party demands defence of Irish waters
The Green Party is demanding that Irish naval vessels be sent off the south coast to ensure that two ships carrying weapons-grade plutonium to France do not enter Ireland's territorial waters.
Party leader Trevor Sargent said assurances given to the Irish Government from the US and France were not enough and that the transport of such a deadly cargo was completely unjustifiable.
The weapons-grade plutonium on board will be recycled into nuclear fuel in France and then transported back to the United States.
The environmental group Greenpeace says it is awaiting the ships with a flotilla. The group may set up road blockades to prevent the plutonium being transported to processing plants in southeast France.