The latest figures released by the Dublin Airport Authority show that up to 1,000 US troops are passing through Shannon Airport daily en route to Iraq.
The Minister for Transport said the stop-overs were simply for refuelling.
Martin Cullen welcomed the growing numbers saying it was good for business.
However, anti-war activists say the Government is turning a blind eye to what is going on.
Last year 125,000 troops passed through Shannon Airport en route to the Gulf and other US bases. That figure is set to be surpassed by the end of this month.
Numbers released for the month September of this year show that 22,525 troops passed through Shannon on 150 flights. That is a 17% increase on the same time last year.
By the end of this year, it is estimated that 350,000 troops will have passed through Shannon in the past three years.