Police are looking for four Australian men after an Irishwoman claimed she was gang-raped in a hotel in Happy Valley on Sunday.
The 21-year-old woman, who works in Hong Kong, was said to have been drunk when she was taken to the hotel from Central, a police source said.
The alleged attack came to light yesterday morning when the victim told her friend at home in Sai Kung and the friend called police.
She was then taken to hospital for an examination.
Initial investigations showed that the woman had been drinking with friends in Lan Kwai Fong on Sunday night and was taken to the hotel after she became drunk.
The four Australians are thought to be aged from 20 to 25 and crime-squad officers are investigating whether the victim knows them.
Wan Chai detectives are investigating the case, which has been classified as rape.
Police figures show reports of rape rose to 83 from 70 in the first eight months this year compared to the same period last year. There were 91 reports in 2011.
Meanwhile, police are still hunting for a taxi driver accused of trying to rape a drunken woman passenger on her way home from Halloween celebrations.
The 27-year-old accountant was driven to a secluded area in Tseung Kwan O after she fell asleep in his cab at about 3.30am on November 1.
When she awoke between 4am and 5am she found some of her clothes had been taken off and the taxi driver on top of her. As she struggled, the cabbie hit her, tied her hands and covered her face in an apparent move to hide his identity.
Efforts to use the taxi network to catch the man have so far ended in failure.
"The taxi unions are very helpful because they fear the incident will damage their reputation," a police investigator said.