Sixteen women from 10 different countries have come forward alleging they were drugged and raped by an Italian police officer who used traveller hosting website Couchsurfing.com to lure them to his property.

Dino Maglio, 35, faces trial for rape after admitting to drugging and having intercourse with an Australian 16-year-old who was staying in his Padua property with her mother and sister.

Now three more cases are being investigated by the case's chief prosecuter, with 16 women having come forward claiming they were attacked by Maglio after arranging to stay with him, reports the Investigative Reporting Project Italy.

Among them are two women from Hong Kong, who allege that Maglio gave them a "special strawberry wine" that knocked them unconscious. He attacked them, then threatened them in his role as a police officer when they posted negative comments about him on the Couchsurfing.com website, reports the South China Morning Post.

"I'm sure he put drugs in our drinks or food but I don't know what he did when we were asleep," one of the women told Hong Kong investigators.

She said she ignored the threat, and began receiving messages from women who also said they had been attacked.

In several other incidents which took place between March 2013 and when Maglio was arrested, victims reported being drugged by Maglio, then waking to find him raping them.

Investigative Reporting Project Italy has collected testimony from alleged victims from countries including the Czech Republic, Canada and Poland.

When police raided Maglio's property, they found two tourists staying with him who seemed to be in a drugged state, as well as child pornography, according to court documents.

Couchsurfing.com claims it is trying to foster "a world made better by travel and travel made richer by connection", and offers users the chance to stay with people around the world offering board and lodging.

The company's chief executive Jennifer Billock told the Guardian that users safety was company's first priority and that the site was were "evolving our tools and processes to find and halt abusers of our system".

"We're reminded that these women could have been any of us, our friends or family," she said.

She urged users to look for verified profiles with multiple positive references.