A refugee on Nauru with a growing lump in her breast has had a medical transfer flight cancelled.
Refugee advocates say the woman was one of 18 on Nauru scheduled to fly to Port Moresby in Papua New Guinea for treatment on Tuesday.
But the flight was cancelled on Tuesday morning and they were told there wouldn't be another flight for at least three weeks.
Doctors for Refugees say the 39-year-old Lebanese mother-of-four has required urgent treatment for the growing lump for more than a year.
She did not want to have the biopsy done in Nauru but was willing to travel to PNG.
Doctors for Refugees convenor Barri Phatarfod said it was a "complete untruth" that people in offshore detention were receiving medical treatment comparable to that in Australia.
Her organisation was reviewing more than 100 cases of concern within the immigration detention system, some of which involved delays of recommended treatment for several years.
"If doctors in Australia treated their patients with the same chaos, lack of follow-up and investigation many would be reported to the regulatory bodies," Dr Phatarfod said.
George Newhouse, principal solicitor of the National Justice Project, described medical facilities for refugees on Nauru and Manus Island as "medieval".
He's investigating a death on Nauru that appeared to have been caused by a delay in the Australian government approving medical evacuation.
"We have dozens of cases of individuals and families suffering in pain without proper care or treatment."
The immigration department has been contacted for comment.
