ASIO power faces challenge

ASIO has branded Tamil refugee Ranjini a direct threat to Australian security, the High Court has heard. The mother of three is being held with her children in a Sydney detention centre but has yet to be charged with any crime.

Details of the secret ASIO assessment were not given in court hearings on Wednesday as lawyers sought to challenge her indefinite detention.

But it emerged in submissions on the case that 10 countries have knocked back government attempts to offload the group of almost 50 refugees ASIO has deemed a security threat.

A total of 47 refugees are caught in what a Labor MP has dubbed a legal ''black hole'' - recognised to have a well-founded fear of persecution at home but not permitted a visa to live in Australia.

Some have been held for four years, but are not permitted to appeal the secret ASIO findings or know the detail of the allegations.

Ranjini, the most conspicuous of the group after being detained while pregnant last year, fled Sri Lanka's civil war and arrived by boat at Christmas Island in 2010.

She lived for more than a year in the community before an April 2012 determination by ASIO that she posed a security risk.

The Commonwealth Solicitor-General, Justin Gleeson, told the court the ASIO finding in her case was of a threat to the security of Australia.

But her lawyers are seeking to challenge the legality of her detention, arguing there is no practical prospect of her being deported.

The court was told in submissions that Immigration authorities only sought out Ranjini's parents - now living in India - after proceedings began, to see whether she could join them. But as refugees, they cannot sponsor migrants.

Another nation, referred to only as Country J, had also refused her resettlement.

The court was told in submissions that 12 nations have been approached to resettle Ranjini and others in the group with adverse assessments - with 10 countries having ''expressly declined these requests''.

The other two countries were approached in May 2010 and their replies remain outstanding. Lawyers say officials concede there is no chance of a positive response.

The countries were not named in court.

Fairfax Media reported in June 2012 that Britain and the US had rejected Australian approaches to settle some of the group - made up mostly of Tamils who fled Sri Lanka's civil war.

The hearing has adjourned for the court to make its decision.