Members of the Oireachtas Petitions Committee have met management at Shannon Airport and senior gardaí from Co Clare about the use of Shannon Airport by the US military.
The three members of the committee said they have been reassured by airport management and gardaí, that within their power, they are meeting their responsibilities about the use of the airport by the US military.
However, committee chairperson Pádraig Mac Lochlainn said further assurances are needed from the Government that Ireland's neutrality is not being compromised.
Mr Mac Lochlainn was speaking after today's separate meetings, which came about following a petition to the committee from the anti-war group Shannonwatch.
The Sinn Féin TD has been accompanied by senators Trevor Ó Clochartaigh of Sinn Féin and Susan O'Keeffe of Labour.
Shannonwatch has called for an independent inquiry into what it perceives as the failure to investigate aircraft suspected of being involved in illegal rendition.
The group said its complaints to gardaí are not followed up.
The committee members were told today gardaí are not permitted to board military planes that carry diplomatic notice, as they have the same immunity as embassies.
The Department of Transport is informed of any civilian aircraft using the airport to transport US troops.
Mr Mac Lochalinn said it was important that Irish people know that any licence granted to either military or civilian aircraft landing in Shannon or elsewhere do not impinge on its neutrality.
He said it was very important to protect that.
The Department of Foreign Affairs regulates the actions of foreign military aircraft in Ireland and 35 countries were given permission to land at Shannon for a year up to July 2014.
They were given permission to land subject to a number of conditions, including that they carry no arms or explosives, that they do not engage in intelligence gathering, or form any part of a military exercise.