A parliamentary inquiry into Australia's immigration detention centres is recommending asylum seekers be detained for no longer than 90 days.

A majority of members of the joint committee say asylum seekers who pass initial health, character and security checks should immediately get a bridging visa or be moved to community detention.

The inquiry also calls for a change to the current situation where the immigration minister is also the legal guardian of unaccompanied children in detention.

Committee chairman, Labor's Daryl Melham, says where possible the maximum time in detention should be 90 days.

"The committee's fundamental conclusion is that asylum seekers should reside in held detention for as little time as is practicable," he said.

"The evidence overwhelmingly indicates that prolonged detention exacts a heavy toll on people, and most particularly on their mental health and wellbeing.

"While academics and psychologists tell us that mental health begins to erode after three months in detention, there are people with adverse security assessments in Australia's immigration system who have been detained for well over two years."

The report also recommends an international medical representative be present at detention facilities 24 hours a day and calls for an independent review of the appropriate qualifications for detention centre staff.

Reasons why

The report recommends that when people are held for more than 90 days, the reasons for their prolonged detention should be made public.

The committee also criticised the regular use of remote facilities, saying asylum seekers in detention should be accommodated in metropolitan areas wherever possible.

"There can be little doubt that, while the use of remote facilities has at times been necessary, they should be used only as a last resort," the report said.

"This will not only better serve the needs of detainees, but save on some of the vast expense required to run large-scale facilities in extremely remote locations."

Greens senator Sarah Hanson-Young, the deputy chair of the committee, has urged the Government to adopt the recommendations.

"The committee was able to agree to removing the guardianship of unaccompanied minors from the hands of the immigration minister, needing to replace that role with someone who will not be seen to be in a conflict of interest, time limits on detention, dealing with the mental health issues, getting people out of remote facilities.

"These are all very practical and much-needed steps."

ASIO scrutiny

The committee wants spy agency ASIO to come under much greater scrutiny, including periodic reviews of adverse ASIO findings.

They also recommended laws be amended to allow for the Administrative Appeals Tribunal to review ASIO's security assessments of asylum seekers.

Mr Melham, a lawyer who has worked in the criminal justice system, says there needs to be someone to guard the guard.

Failures

The majority of the report was supported by Labor and Greens members of the committee, along with independent MP Rob Oakeshott.

The Coalition has supported only 16 of the 31 recommendations and has issued a dissenting report.

Opposition immigration spokesman Scott Morrison says problems in detention centres have increased because of the number of asylum seekers coming to Australia.

"Our detention network collapsed because simply too many people turned up on too many boats as a result of Labor's border protection failures," he said.

Mr Morrison says the committee was set up after immigration detention riots last year, but he does not think it has focused enough on that aspect of the detention system.

"I've focused very heavily on the riots in my statements today because they have not been focused on, I believe, in the majority report made public today," he said.

"The Australian people particularly wanted answers as to how and why this happened, so firstly it was because of the Government's decision to abolish the border protection regime of the Howard government."