The Irish Travel Agents Association is reminding all Irish passport holders they will need a valid electronic passport if they want to visit America, or secure a visa.
New rules requiring all Irish people who are able to travel to the US via the Visa Waiver Program to have an electronic passport come into effect today.
Those who do not have a valid electronic passport are still eligible to travel, but will need a valid non-immigrant visa issued by a US embassy or consulate.
ITAA CEO Pat Dawson urged all people travelling to the US to check their passport before departure.
He said: "I believe there are 171,000 that fall into the gap. Those travelling to the US in the next week or two should contact the US Embassy to get their visa allocated."