Fewer people will apply for J1 visas after changes to the programme, according to the Union of Students in Ireland (USI).
The union added it was very disappointed with new rules which mean students will have to have been offered a job before they leave Ireland in order to gain entry to the US.
Students will have to show job papers to booking agents before they can apply for the J1, which has been in existence for 50 years. Some 7,000 Irish J1 students travelled to the US last year, the highest number from a single country.
USI President Kevin Donoghue said the new measures would make it more difficult for students to travel on a J1 visa.
He said: "It's one of those opportunities that allows people to develop (and) be exposed to other cultures.
"It's good for American society as well to engage with Irish people.
"(However,) the infrastructure isn’t there to ensure people who are looking for work will get it, so we would be worried there won’t be as many able to avail of the J1 programme next year as a result of the new measure."
A USIT advisory says students should start applying as soon as posisble if they want to travel in 2016.