An Italian policeman who posed as an amiable host on the Couchsurfing.com website has been charged with drugging and raping a 16-year-old Australian girl and may have done the same to up to 15 other women, judicial sources say.

Dino Maglio, 35, will stand trial in Padua near Venice from March 17 on charges of raping a minor with the aggravating circumstance of having administered a narcotic without her knowledge, prosecutors in the northern city said.

The case is set to reignite safety concerns surrounding Couchsurfing, a social networking site that puts travellers in touch with hosts who are willing to put them up and show them around their hometowns for free.

Its declared aim is "a world made better by travel and travel made richer by connection", but its model has been criticised in the past because of incidents of travellers being attacked by hosts they knew nothing about.

The alleged rape of the Australian girl occurred in March last year.

The girl's mother told police she did not believe there was any reason for concern as Maglio was himself a police officer.

The teen is understood to have stayed up chatting to Maglio while her mother and younger sister, who were also staying at his apartment, went to bed.

After his arrest, Maglio admitted to having spiked the girl's drink and to having sexual intercourse with her, knowing she was a minor.

He claimed that the sex had been consensual, judicial sources said.

Fears for other women hosted by Maglio

Prosecutors investigating the case of the Australian teen are now also considering possible further charges arising from a suspected attack that occurred after Maglio was charged, and statements about similar incidents made by 14 women from seven countries to the Investigative Reporting Project Italy (IRPI).

"Three of the women – all Czech nationals – have so far filed rape charges and we are looking at the evidence presented by the other women," a judicial source said.

An American student, who also said she was raped, made a statement to police in London following her return to the UK, where she was a resident.

Couchsurfing's chairwoman Jennifer Billock responded to the revelations in an email.

"These horrific crimes hit close to home on a deeply personal level for everyone in the company," she said.

"We stand in solidarity with these women and with all women everywhere who have been the victims of violent crimes, and we applaud their courage and tenacity in pursuing justice."

Maglio has been placed in pre-trial custody.

AFP