Two Government planes are on standby in Malta to evacuate 40 Irish citizens trying to flee Libya.
The Casa aircraft and LearJet with nine crew members are in Valetta awaiting the green light from diplomats to fly into Tripoli.
The two planes and additional crew members flew into the Mediterranean island overnight.
The Defence Forces are liaising closely with Department of Foreign Affairs officials as they attempt to get clearance to land in the troubled north African state.
About 40 Irish nationals in Libya are seeking to leave as ruler Muammar Gaddafi ruthlessly cracks down on protests over his 42-year autocratic regime.
The Irish Casa aircraft, routinely used for fisheries patrols, can carry 21 people and the LearJet eight.
"The LearJet was dispatched with a spare crew for the Casa if a window of opportunity arises," a Defence Forces spokesman said.
"We are liaising with the Department of Foreign Affairs and as soon as they give the green light through their channels we can move."
Outgoing Taoiseach Brian Cowen approved the immediate deployment of the two Air Corps planes last night.
A Government spokesman said: "The decision follows increasing concern in relation to their safety arising from the latest assessment of the deteriorating political situation in that country."
Foreign Affairs officials have been liaising with European Union counterparts to establish options to assist citizens and help them leave the country safely.
The evacuation is being co-ordinated by Pat Hennessy, the Irish ambassador in Rome who is accredited to Libya.
The group includes at least six Irish workers in Libya's second city Benghazi with Dublin-based firm Mercury Engineering.
Four women who hold Irish passports are long-term residents in the city and married to Libyan men.
More than 200 people have been killed in the past two nights of clashes on the streets of Libya, with Colonel Gaddafi vowing to fight "to my last drop of blood".
The Department of Foreign Affairs has advised against all travel to Libya and warned Irish citizens who are already in the country to leave.
Anyone who has any concerns over family or friends in Libya can contact its Crisis Centre on 01 4180222.