The agency has joined several human rights organisations in criticising the Strengthening Information Provisions Bill, which was introduced by the Home Affairs Minister Peter Dutton last year, and has been challenged in parliamentary committee hearings this week.

The proposed laws would give the government the power to keep secret some types of information used to cancel visas or citizenship.

If the bill passed, the government could rely on confidential information from intelligence and law enforcement to revoke citizenship or refuse a visa, and prevent that information from ever being disclosed - including to the person who needs the visa.

Legal Aid submitted the changes would, in some cases, make it virtually impossible for people to challenge a decision to refuse or cancel a visa on character grounds.

It said this could lead to people being left in prolonged detention, or refugees being forcibly returned to their home country in contravention of Australia's human rights obligations.

It also says the bill will undermine long-held principles that fair hearings are in the public interest.

But the Department of Home Affairs has submitted the disclosure of confidential information by law enforcement and intelligence agencies could cause severe damage to the public interest, potentially jeopardising active investigations.

It argues the government needs greater powers to manage the risk posed by what it describes as "migrants of character concern".

It says the courts would be able to decide how much weight to give any secret information when people's cases are under review.

The bill was referred to the Senate legal and constitutional affairs committee on Thursday.

Australian Associated Press