BERLIN ?- Festival goers at a nationalist, right-wing concert in Germany were taken by surprise when souvenir t-shirts they were given had a secret anti-far right message that emerged only after being washed.

The slogan on the shirts first read "hardcore rebels" along with a skull and nationalist flags. But once washed the slogan turned into a message from a group offering help to right-wing extremists break away from the neo-Nazi scene.

"If your t-shirt can do it, you can do it too -- we'll help you get away from right-wing extremism," reads the slogan on the shirts after their first washing. ?

The anti-far right shirts were handed to 250 people at a "Rock for Germany" concert in Gera by organisers after they had been donated anonymously. They were provided by EXIT, a group which helps people disassociate themselves from the far-right.

Festival organiser Gordon Richter of the far-right NPD party said the stunt was a waste of money.

"It's kind of pathetic that anyone spent money for something like that," Richter told Reuters. He said many who got the Trojan horse shirts thought it was a creative idea.

Bernd Wagner, founder of EXIT, said the t-shirts were designed to reach their main target group: right-wing extremists contemplating getting away.

"We wanted to raise awareness about our programme, especially among the young and less committed," Wagner said.