Asylum seekers and refugees detained in Nauru will only be transferred to Australia for medical treatment if they are at risk of dying or a permanent disability, documents obtained by ABC reveal.
The documents suggest the Australian Border Force was imposing the tough condition.
And it appears that most medical cases are being transferred instead to Papua New Guinea.
International Health and Medical Services, the company the Australian Government contracted to provide medical services to detainees on Nauru, wrote in an internal email that "Government will now only approve medical transfers to Australia if refugees or asylum seekers are likely to face permanent disability or death".
"IHMS needs to find the next five or six urgent outstanding cases for transfer and add to the clinical case review list for next week," Dr Heather Miller, medical director of IHMS, wrote in the email.
"ABF have advised they will only transfer to Australia if the condition will lead to permanent disability or death."
When asked about the email, IHMS directed questions to Australia's Immigration Department.
The Immigration Department said refugees were eligible for the Government of Nauru Overseas Medical Referral process if required medical services were not available there.
And they said that process was managed by the Government of Nauru.
ABC sought a comment from the Government of Nauru, but have not received a reply.
This week, in a , a doctor working on Nauru slammed what he called "a broken system", after being unable to organise an MRI for his patient waiting for 10 months to be examined.
'I don't know why they took him to PNG'
"Mohammed", a Lebanese refugee who did not want to be identified, has been in a Papua New Guinea hospital for the past two weeks, with a serious leg injury.
His brother "Joseph", who lives in Australia, said he was worried about him.
"My brother has problem in his knee, and it's hard for him when he walks, when he moves, it's hard for him," his brother said.
Joseph said Mohammed had been living on Nauru for four years, and for a year-and-a-half he was in immense pain.
Mohammed told the ABC that specialists who visited Nauru with the International Medical Services had recommended surgery on his knee straight away.
"When I saw the specialist he said I need to have an operation and that should be done as soon as soon," he said.
But he said the Australian Border Force told him a week before that he would not be going to Australia as expected, but to Papua New Guinea for treatment.
"They told me I am coming to PNG for a medical assessment … they didn't say why," he said.
"My mental health is really bad, and every day it is really bad."
Both he and Joseph had expected Mohammed to be flown to Australia for the operation, but instead he was sent to a hospital in Papua New Guinea.
"I'm shocked of this situation. I got shocked when they sent him to PNG because [anyone] who want to do an operation or medical treatment, they should bring him to Australia," Joseph said.
"I don't know what happened, I don't know why they took him to PNG."
Joseph said he was calling Mohammed weekly.
"Doctors told him 'we need to do the operation here', but he is scared and said 'I don't want to do anything here, I need somebody next to me from my family'," he said.
"They told him 'do whatever you want to do, we're not going to send you back to Australia. You will be here or we'll send you back to Nauru'."