The Abbott government has disbanded a key group that provided advice on the health of asylum seekers in detention, as research reveals psychiatric problems - such as self-harm - are the most common reasons for the large number of detainee visits to hospital emergency departments.

Members of the Immigration Health Advisory Group (IHAG) received letters late on Friday telling them the group would be dissolved and replaced by one adviser.

Dr Paul Alexander, the group's chairman and a former head of Joint Health Command in the Defence Force, will become the sole independent health adviser to the Immigration Department.