This year's Electric Picnic sold out in two hours after festival fans devoured all 55,000 tickets - before the line-up was even announced.
Headlining the September 1-3 event at Stradbally Hall will be 1980s stars like Duran Duran and Madness alongside The XX, Pete Tong, Chaka Khan and Interpol.
Tickets went on sale at 9am yesterday but were all snapped up by 11am, nearly an hour before the headline acts were unveiled.
However, shortly afterwards tickets were being sold by touts on secondary ticketing site Seatwave, a Ticketmaster-owned company.
Weekend camping tickets which had originally been priced between €160 and €200 are now appearing on Seatwave for as much as €600.
Festival director Melvin Benn said he discouraged this sort of activity but said until the law changed there is little to be done about it.
Mr Benn was delighted with the reaction to this year's event and said he never assumed it would sell out so quickly.
"I don't take for granted we'll sell out and I'm grateful there are still more than 55,000 people who want to come to Picnic," he said.
"To be honest, I thought I'd left enough tickets to go on sale that they would run for a month so I'm really happily surprised that they've sold out in a day.
"It says a lot about the experiences that people have at the Picnic. It has a net worth of €36m to the Irish economy and that feels very special."
While he said he will be making a few changes to the festival this year, Mr Benn dismissed speculation that they would be increasing its capacity.
"It's not getting any bigger, because we feel it's OK where it is at 55,000. I'd need to reshape it even more to get more people in.
"It feels right at 55,000 people this year and I think it will next year too," he said.