The mysterious case of a man imprisoned in the ACT last year in a process which was hidden from the public, is raising questions over whether more such "secret trials" are taking place in Australia.

It is understood that the prisoner, given a pseudonym of Alan Johns, was a former intelligence official, but details about his crime and background have been kept suppressed.

Interview with: Stephen Blanks, spokesperson, New South Wales Council for Civil Liberties, Brian Toohey, author and Michael Shoebridge, defence director, Australian Strategic Policy Institute