The Safe Harbour Outreach Program said it took the unusual step of issuing a public alert to sex workers in St. John's because of the severity of the alleged sexual assaults and because they have received several reports.
Program co-ordinator Laura Winters said sex workers, both women and men, have been approached online or on the street and are taken to a hotel on the understanding they will be meeting one person.
Winters alleges when the sex worker arrives, they are forced into a room where up to 20 men are waiting.
"Really, gang rape is what it is," said Winters in a phone interview on Friday.
"We're hoping the men involved see this and know that this is totally unacceptable and that these people deserve respect and deserve protection like everyone else in society."
Winters said the workers did not want to file a police report, but police contacted the program after seeing the public warning on Twitter and have offered their resources if needed.
The Royal Newfoundland Constabulary said they're encouraging the alleged victims to come forward.
Const. Steven Curnew said their priority is the safety of the women and men and they will not be prosecuted for their work if they file complaints with the police.
"We take these types of crimes very seriously," said Curnew. "Even though they are people within the sex trade industry, we're sensitive to these issues.
"Our objective is not to prosecute (the sex workers), it is to bring the people responsible to justice."
Winters said initially there were two reports of sexual assaults, but since posting the warning online several other sex workers have called to say they had similar experiences.
"Part of the danger is that people feel they cannot report this kind of thing to police," said Winters. "So hopefully if it's happened to them, they feel that (the Safe Harbour Outreach Program) is a safe place to come forward with the information."
Winters said it is believed the men are associated with a crew working on a major construction project in the province, although she would not say which one.
She said she also thinks the men involved believe they won't get caught.
"These are not disposal people," Winters said of the sex workers. "These are members of our society that deserve the same rights, the same respect and the same safety that everybody does."
— By Aly Thomson in Halifax
Follow (at)AlyThomson on Twitter