The US Department of Homeland Security has announced that from the end of next month, travellers from Visa Waiver Programme countries, including Ireland, must have a machine-readable passport.
New rules requiring machine-readable passports were introduced in October 2003, but customs officials had the discretion to allow travellers enter the US on an old-style passport.
This flexibility will no longer apply from 26 June.
Airlines that permit travellers on old-style passports to board flights to the US will in the future be penalised $3,300 per passenger.