The 17-year-old from Guinea told investigators she was flown to Sydney via Paris in early April after a man in her home country offered her a job as a cleaner in Australia.
The pair traveled together from Guinea and upon arrival, the man drove her to a house police believed was in the Sydney area where she was 'kept in a room and sexually assaulted by a number of men,' the police said in a statement.
The teenager, who was not named, escaped from the house in the early hours of April 27. She ran until she was picked up by a woman, who drove her to an asylum seeker center.
Police officers from the human trafficking and sex crime units were looking into how and when the girl arrived in Australia, as well as the alleged sexual assaults, the statement said.
A spokeswoman for the New South Wales police contacted by the Thomson Reuters Foundation could not give further information on the case.
Police are searching for the man who the girl traveled with and urged the woman who picked up the teenager to come forward.
Australia is home to an estimated 4,300 victims of forced labor, sexual exploitation and domestic servitude, according to the 2016 Global Slavery Index by Australia-based rights group Walk Free Foundation.
Globally, nearly 46 million live as slaves, forced to work, sold for sex, trapped in debt bondage or born into servitude, according to the group.