Anti-war activists are to picket the offices of the Irish Aviation Authority (IAA) in Dublin today over the refuelling of US warplanes at Shannon airport.
Over 330,000 US troops passed through the hub during 2005 - more than double the number for 2004.
Pressure has been mounting on the Government to search the flights for military weapons or terror suspects en route to alleged CIA interrogation camps.
Minister for Foreign Affairs Dermot Ahern has insisted the Irish Government accepts the assurances of US authorities that nothing untoward is taking place. He called for credible evidence of any wrongdoing to be passed onto the gardaí.
Pitstop Ploughshare spokesman Ciaron O'Reilly, who organised today's protest, said the use of Shannon airport was increasing Ireland 's involvement in the war in Iraq.
"The Government is pulling the country deeper and deeper into complicity for the illegal war," Mr O'Reilly said.
Anti-war protesters previously staged a sit-in at the Aviation Authority building during the Ramadan festival in 2003.
A new Peace Camp is to be re-established at Shannon airport this weekend.
Local Co Clare councillor Martin Conway has called for members of the Defence Forces to be deployed at the airport to search US military aircraft.
Influential US academic Noam Chomsky has also questioned whether Taoiseach Bertie Ahern is following the will of the Irish people or following orders from Washington by allowing the stop-overs of US warplanes.
Speaking in an interview recorded last May but published last week, Dr Chomsky added: "It refuelling of US military aircraft can only be justified if the goal of the Government is to be the obedient servant of the global superpower [the US]."