Members of the Shannonwatch organisation have told the Oireachtas Joint Committee on Public Service Oversight and Petitions that gardaí have told them that they have been instructed not to search US military and CIA planes at Shannon airport.

The Shannonwatch representatives, Dr Edward Horgan, Margaretta D'Arcy and Dr John Lannon, provided the committee with a list of what Dr Lennon said was over 40 complaints of suspected rendition planes at Shannon, which he said went unanswered by gardaí.

Dr Horgan told the committee that a number of senior gardaí, including a Detective Superintendent, attributed the instruction to a letter of advice from a former attorney general to the then garda commissioner.

However, Dr Horgan said questions to the office of the Attorney General on this matter and "did not get a satisfactory response".

Dr Lannon said that Shannonwatch was asking for clarity on this matter.

He recommended to the committee that "the State should provide comprehensive information on all complaints made to gardaí in relation to aircraft suspected of being involved in rendition planes or were suspected of carrying munitions that were illegal ... planes that basically are in violation of international law and international law".

Responding to a question from Senator Susan O'Keeffe, who quoted a letter from the Department of Foreign Affairs on Ireland's record in investigating complaints of planes suspected of being used for rendition, Dr Lannon said that while the department had said all complaints had been fully investigated, it was being selective by only mentioning a small number of complaints.

On behalf of Shannonwatch, Dr Lannon called for an independent inquiry into the alleged use of Shannon in the CIA's rendition programme.

He said the Government should review and strengthen the procedures for the inspection of planes, and he called for the full disclosure of all agreements that are currently in place with the CIA and US military in relation to the use of Shannon airport.

He also called for neutrality to be enshrined in the Constitution.