The musician was arrested after a fight broke out when the band had finished playing. Nobody was seriously injured in the fight.
"The suspect denies committing an offence," police spokesman Bo Olsson told The Local.
Olsson added that the alleged assault was of a minor nature. Had the suspect been a Swedish citizen he would not have been held. But because there was a risk he might flee the country, the public prosecutor ruled that he should be detained.
"He can be held for up to 36 hours," said Olsson.
The incident took place backstage and did not involve a fan, according to Debaser's managing director Annelie Åkerstedt.
"Jerry Tineo (Ju-Ju) was arrested after a fight with someone connected with the band," Åkerstedt told AFP.
She rejected the musician's assertion that the security guards had not done their job properly.
"That's pure bullshit. The security did the job they are supposed to do. They didn't let anybody backstage who wasn't supposed to be there. They intervened quickly and called the police, exactly as they should," Åkerstedt told Expressen.
The two members of The Beatnuts, Psycho Les and Ju-Ju, originally joined forces in 1989. Their debut album, Intoxicated Demons, was released in 1993.