Security guards at Australia's detention centre on Nauru allegedly circulated videos of themselves having sex with asylum seekers who had been paid to participate, a former senior social worker on the island has claimed.

Charlotte Wilson was, until February this year, a Save the Children case manager at the Nauru Regional Processing Centre. In her explosive submission to the Senate inquiry, which is investigating allegations of abuse at the facility, she claims to have been told it was "acknowledged in management meetings between service providers" that acts of "solicitation" were occurring in the community between female refugees and Australian security officers employed by Wilson Security.

Ms Schmidt-Nielsen said it was "deeply undemocratic" for a government to cherry-pick which foreign MPs were allowed to visit Nauru. Credit:Angela Wylie

"It was also established that these acts had been filmed and circulated around Wilson staff," she said, of the rumours that began to circulate in January. She added: "I was also told that because prostitution is legal on Nauru that no action was being taken against the staff members involved."

In her submission, which hasn't yet been made public but has been obtained by Fairfax Media, Ms Wilson alleges she witnessed a security guard tell a group of single Somali women that if they run away, they would get "raped by the local boys".