John-Paul Sanggaran last year helped prepare a 92-page letter, co-signed by 14 other doctors who had worked on Christmas Island, which highlighted concerns about standards of care on the island.
He worked as a medical officer on Christmas Island for 10 weeks last year and co-authored a letter expressing concerns about the standards of medical care and practices at the island's Immigration Detention Centre.
In a public talk at the University of NSW, Dr Sanggaran has raised his concerns again.
He says asylum seekers taken to Christmas Island could expect to be bundled off boats, rushed through medical assessments and separated from important medical records and medicines.
"The volume required to be processed is medically dangerous. As predicted by peak bodies such as the Royal College of Physicians, these assessments are completely unreliable and errors occur."
Dr Sanggaran is highly critical of the behaviour of some nursing staff who he saw dealing with asylum seekers on Christmas Island.
He says medications were routinely taken from asylum seekers and thrown away.
According to the doctor, no records were kept of what medications were being destroyed, or who they belonged to.
Dr Sanggaran says he also observed that medical assessments were done in a way that he believes neglected patient care and dignity.
"The norms and standards of medical practice are so distorted when in this environment that mass prescription without discussing the purpose of the drug is something that I got half way through myself before waking up to the fact that it was both unethical and dangerous," he says.
Dr Sanggaran says asylum seekers not receiving adequate medical treatment included children who appeared to be mentally ill, and pregnant women without access to the basics of anti-natal care.
He says the concerns raised in the letter appear do not seem to have been taken seriously by the federal government, or the group contracted to provide medical services on Christmas Island, International Health and Medical Services.
Despite 18,000 words of detailed concerns, there has been no adequate response.
He added that there were others who were keen to speak out but were frightened to do so.
"I in fact fear repercussions because I have spoken out. It is those same fears born of confidentiality clauses and contracts and the culture of secrecy that serves to silence, that prevents good people from raising their voices,'' he says.
Immigration Minister Scott Morrison says the matters raised in the letter were directed to International Health and Medical Services.
