"In the heated, protracted battle over the Australian Building and Construction Commission, it can be hard to separate fact from fiction. When I first looked at the law that underpins the commission, I expected many of the strongest attacks to be wildly overstated. I was wrong.

By any standard, the ABCC is a remarkable body. Described as a ''tough cop on the beat'', it has powers that greatly exceed those given to any police officer in the nation.

The ABCC can force people to answer questions in secret and to reveal documents that relate to any of its investigations. This negates a person's right to silence. It also removes their privilege against self-incrimination, a protection that has been described by the High Court as a ''cardinal principle of our system of justice'' and a ''bulwark of liberty''.

Disobeying the ABCC is punishable by six months in jail. This is the penalty facing a South Australian rigger, Ark Tribe, whose trial for failing to attend the commission for questioning continues later this month.

There are no limits on the type of information that can be sought by the ABCC. A person can be compelled to hand over personal phone and email records, reveal memberships of a union or political party, and report on private meetings.

This can be applied to anyone. Workers can be brought in, not because they are suspected of wrongdoing, but to report on the activities of their co-workers. Family members, including young children, can be told to reveal information about a parent in the building industry.

The possibilities are far reaching. The law even means that a priest can be forced to reveal the secrets of the confessional. Such examples are not entirely fanciful. One person who just happened to be passing a building site was reported in this paper to have been ''hauled in for several hours of secret questioning'' after seeing a confrontation between a union official and a building manager.

In case there was any doubt about the scope of these powers, the law says that the ABCC can override the protections that innocent people have under privacy law. The law may well be unique in also allowing the commission to ignore the confidentiality of cabinet documents and to demand secret national security information held by agencies such as ASIO.

The problem is not just one of extraordinary power, but also that the expected safeguards have been stripped away. Unlike other bodies that question people, the ABCC does not need a warrant from a judicial officer or other independent person. The normal grounds of reviewing its decisions have also been excluded, meaning federal law cannot be used to argue that the ABCC has breached the rules of natural justice or made a decision in bad faith.

What is most surprising is this unchecked authority is not directed at serious crime. The ABCC's mandate is instead to investigate industrial matters in the construction industry. This means it can use its coercive powers to inquire into minor breaches of industrial awards, including the proper taking of sick leave and rest breaks.

Despite its limited role, the ABCC has been given powers that would not be contemplated for the police by a state government bent on winning a law and order auction. This should be a concern to everyone, not just people working in the building industry. A dangerous precedent has been set that could well be applied elsewhere.

The ABCC was created by the Howard government after the Cole Royal Commission into the Building and Construction Industry reported in 2003 that it had found examples of ''lawlessness''. This finding is disputed by the union movement. However, even if it is correct, the powers given to the ABCC represent an overkill.

Labor vehemently opposed the creation of the commission. It has since changed its approach. In government, Labor has sought to put new restraints on the body, but has made no move to abolish the powers of the ABCC or to ensure that all workers are subject to the same laws.

Kevin Rudd was steadfast in holding to this position. He did so despite calls from across his own party and the union movement that the ABCC be dismantled. Julia Gillard is now facing renewed pressure, including from her backbench and some of her most prominent union supporters. They are asking her to go to the next federal election seeking a mandate to abolish the ABCC and its powers.

The Prime Minister should do so. The ABCC has no place in a modern, fair system of industrial relations, let alone in a nation that prides itself on political and individual freedoms.

George Williams is the Anthony Mason Professor of Law at the University of NSW"