All but one of the medical professionals advising on the health and well-being of asylum seekers have been sacked, following a purge that could leave thousands at risk.

The Federal Government has axed the Immigration Health Advisory Group (IHAG), which was formed in 2006 to provide independent advice on the health and mental health needs of asylum seekers and others held in Australian detention centres.

Members of the board say they were caught totally off-guard by the decision, and are now worried that there will be no adequate protection for the health of many being kept in detention.

The group consisted of medical experts in several fields, psychiatrists, psychologists and GPs, as well as rights advocates and officials. IHAG first came together following the Palmer and Comrie Inquiries into mishandled health services for refugees.

“The group was informed on Friday that it has actually been disbanded, which is of course an issue of grave concern to the medical and health professionals involved,” Professor Louise Newman, a member and former chair of IHAG.

“It's extremely concerning when we have the major people within the health and mental health professions who are experts in this area, being in a sense advised that our advice is not perhaps necessary or needed.”

It is understood that IHAG’s current chair, Dr Paul Alexander, is the only board member to survive the cull. Reports say that a new panel will be set up around Dr Alexander, an Australian Defence Force medical expert.

Prime Minister Tony Abbott says the bigger group was not helping, and having just one person providing advice is better.

“There was a committee which was not very effectual,” Abbott said.

“The chairman of the committee is now the departmental medical officer who is providing advice in a more sustained way.”

“So we are still getting the advice; we're getting the advice in a more sustained way from the chairman of the committee rather than needing to have a full committee to do it for us,” the Prime Minister said.

The Australian Psychological Society's representative to IHAG says that Dr Alexander, while an expert in his field, lacks a thorough knowledge of mental health issues.

“We are very concerned that people's mental health needs will be completely unattended to and no one will look after them,” Australian Psychological Society Adjunct Associate Professor Amanda Gordon said.

Recent research has shown that self-harm, depression and other psychological and mental health issues are the most frequent reason for treatment in detention centres.

“I guess I'm concerned that Dr Alexander doesn't have a background in mental health at all.

“In fact they are being only cared for in terms of security and that they are individuals human beings who are going to be pawns to Government policy.”

The move to abolish the asylum seeker health advisory group comes just days after Amnesty International released this report  condemning the conditions at one detention centre as cruel, inhuman, degrading and in violation of international prohibitions against torture.