The Department of Transport is examining reports that weapons bound for Israel flew through Irish airspace.
The Ditch news website claims there were four flights from the US with ammunition on board for the Israel Defence Forces (IDF), which travelled through Irish airspace.
A spokesperson for the Department said it is investigating, adding no such applications or exemptions had been granted this year or last.
The Department said the carriage of munitions through Irish sovereign territory or airspace by civil aircraft is prohibited without a special Government exemption.
The spokesperson said the Department is aware of media reports, and “engaging with the carrier concerned”.
Taoiseach Simon Harris has said any such passage would be subjected to “clear consent protocols”, adding that he had been consistently told there have been no requests to transport munitions to Israel across Irish airspace.
The Ditch reported the flights were carrying detonating fuses, teargas primers, ammunition primer and explosive charges.
Speaking on Tuesday, Mr Harris said: “It is very important now that the facts are established.
“The Department of Transport has confirmed today that it is now engaging with the carrier.
“Once those facts are established, of course it could be for the Minister for Transport and the Minister for Defence to provide a further update on this and I’ll certainly be keeping in contact with both of them.”
Professor Scott Lucas from the Clinton Institute said the Irish Government may have decisions to make.
Prof Lucas told Newstalk: "You either then have to say, 'Oh, OK, America that's fair enough. You can keep on delivering these weapons, including some used as offensive weapons, as we have this open-ended war, including on civilians in Gaza.
"Or the Irish Government has got to take a stand against an ally, the United States, and say, 'no, sorry, you're going to have to route the aircraft around Irish airspace, or you're going to have to give us a good reason to give you an exception'."
