More than 20,000 people are expected at Escape into the Park

Organisers of the Escape into the Park event are working with police to try to trace the source of the forgeries.

More than 20,000 people are expected at Singleton Park on 14 August when over 60 DJs will be performing.

There are also fears fake tickets may be available for Pop in the Park featuring Busted the following day.

There will be more checking of tickets and more police officers and security stewards will be redeployed to assist in those checks Jonathan Wignall

Event organiser Jonathan Wignall said a small number of counterfeit tickets were recovered at last year's event.

However, he added: "It's getting to the level that the people making the forgeries have decided it's worthwhile them doing.

"We had a lady in the office yesterday that had bought 42 fake tickets. She said she was aware of another 2,000 that she could get hold of.

"We will be doing all we can on the day. Those with forged tickets will not get in unless they pay again on the gate and I don't want people having to pay twice.

"There will be more security on the day. There will be more checking of tickets and more police officers and security stewards will be redeployed to assist in those checks."

Mr Wignall said the fakes were easy to spot.

They are believed to be changing hands at �20 each rather than the �35 printed on the ticket.

Busted will headline the following day's Pop into the Park event

"With the genuine tickets if you hold them up to the light you will see a water mark. The back of the tickets are also off white but the forged tickets are white on the back," he added.

"We would advise anyone who does not have a ticket not to buy from anywhere other than official sources or they may well lose their money."

He said there was also concern for the following day's Pop in the Park event which is being headlined by Busted.

The same tight security measures will be in place then.

Detective Inspector Paul Henwood of South Wales Police CID said officers were trying to trace the source of the fakes.