It's reported detonators for the Israeli forces were on board.
Three flights with ammunition for the IDF flew over Irish airspace this year according to the Ditch news website.
This comes despite a recent declaration by the Taoiseach, Simon Harris in the Dail, that such practices were not happening.
Sniper ammunition and exploding bridge wire detonators were among the weapons on the flights from the US to Israel.
A spokesperson for the Department of Transport says the carriage of munitions' of war is prohibited on any civil aircraft in Irish sovereign airspace unless an exemption is granted.
The Taoiseach also recently said that any potential exemptions would not be granted in relation to Israel.
The Department adds that no such applications have been received or granted to or from Israel this year.
It is now investigating the claims and is engaging with the carrier concerned.
