Traffic on one of the main routes to Electric Picnic is already very busy.
A breakdown on the M7 is adding to delays already caused by construction works on the road out of Dublin.
Around 55,000 people will travel to the festival this weekend to watch acts like Kendrick Lamar, Massive Attack and The Prodigy.
Elaine O'Sullivan from AA Roadwatch is advising drivers to give themselves plenty of extra time for their journey.
She said: "There are reports of a breakdown between junction nine and junction 10, so that could be adding to problems.
"It is already busy also both ways passing junction 10 now. Keep in mind if you are using the N7/M7 heading to the Picnic over the weekend, we have reduced speed limits in place both ways between junction 8 Johnstown and junction 11 M9 as part of ongoing works there.
"This will slow traffic between those junctions."