About 150 tennis fans were ejected from the Australian Open on Monday after Croatian and Serbian fans became rowdy, police said.
Police said "unfamily like behaviour" by Croatian and Serbian fans in the public garden area of the venue prompted police to take a "proactive stance" and eject the fans.
"They were mostly Serbians ejected as they were upsetting the Croatians," said Victoria state police spokeswoman Katherine Jess. "Police are now meeting with Tennis Australia officials to work out the next move."