"We had an enormous amount of messages, particularly from female guests, who complained of sexual harassment and bad attitudes," Ingmari Pagenkemper, Managing and Artistic Director at the Södra Teatern club on Södermalm, told The Local.
Security staff had regularly been ejecting people identified as gropers or troublemakers, she said – sometimes as many as 15 on a single night – but the combination of darkness, loud music, and a large venue occasionally made it difficult to identify those responsible.
Only some of Södra Teatern's club nights had been affected; the venue declined to specify which ones, and Pagenkemper said she didn't know why certain events appeared to attract offenders. The events in question had been held regularly at Södra Teatern for three years, with the number of complaints increasing significantly over the past four to six months.
"For some reason, some nights with a certain kind of music attracted large groups of men who can't behave themselves - I really don't know why," said Pagenkemper. "But it is unacceptable to have guests or staff feeling unsafe."
"We are working on finding a solution that allows us to protect our guests while continuing to be an open, democratic, warm venue," she explained. "We could be tougher on the door or have a strict guestlist, but that's not what we stand for."
"We don't want to reject people based on how they look or assumptions about what they might do. We're proud to offer such a diverse range of events and we welcome everyone – except those who can't behave."
With its rooftop bar offering views over the city, Stockholm's oldest theatre is one of the city's most popular venues during the summer months, with events ranging from jazz and theatre shows to indie, electro and alternative club nights.
Sexual assault in Sweden, particularly at concerts and festivals, has been thrust into the spotlight recently.
Swedish festivals saw high profile reports of sexual crimes last year, including at the popular Bråvalla festival in Norrköping, the Putte i Parken festival in Karlstad, and Stockholm youth music festival We Are Sthlm.
Differences in the way sexual crimes are reported in different countries have led some right-wing factions in the UK and US to label Sweden as 'the rape capital of the world'.
Police were also heavily criticized when it emerged they had failed to release details on the 36 reports of sexual assault and two rape allegations filed after the We Are Sthlm festivals in 2014 and 2015.
Last year, police handed out 'anti-groping' wristbands ahead of the summer festival season, aimed at raising awareness of the problem and getting potential perpetrators to think twice.
ANALYSIS: Sweden's crime stats for 2016