Attorney-General George Brandis says a Royal Commission into trade unions will tackle the "systemic", "ingrained" corruption in the labour movement.
And he has accused federal opposition leader Bill Shorten, a former trade union leader, of opposing a Royal Commission because he was the "nominee of the trade union movement".
Senator Brandis confirmed on Sunday the announcement of a wide-ranging judicial inquiry was imminent, declaring it would be "irresponsible for the government not to respond in an appropriate way" to public concerns.
The inquiry would examine allegations of impropriety at the health services, construction and Australian workers unions.
"You have judicial inquiries or royal commissions where there is a systematic and ingrained cultural pattern within an institution that needs to be exposed," he told Sky News.
"The revelations we have seen in recent months suggest it [corruption] is much more widespread and systemic and an ingrained problem with the trade union movement."
Mr Shorten has proposed a multi-jurisdictional taskforce, led by the Australian Federal Police and include state police forces, to investigate the corruption allegations.
The opposition leader said on Sunday his party had no tolerance for bribery, extortion or criminal behaviour.
‘‘No one is welcome in the labour movement if they are engaging in any form of criminal behaviour,’’ he said.
“Labor is asking the government to set up a police-led taskforce to deal with these issues. We believe a $100 million-plus Royal Commission is a political stunt that doesn’t do anything to assist with law and order,’’ Mr Shorten said. ‘‘This is a job for police, not politicians.”
Australian Council of Trade Unions president Ged Kearney said a royal commission suited the government’s political purposes.
“Australians are very cynical about this,” she said.
“They'll know this for what this is. This is nothing but a witch-hunt designed to weaken unions to stop unions standing up for decent wages so that Australians can maintain a decent standard of living."
Senator Brandis dismissed Labor’s proposed joint taskforce as "lame" and highlighted Mr Shorten’s close ties to the trade union movement.
“You'd expected Bill Shorten to protect trade union bosses because Bill Shorten was a trade union boss and is only the leader of the Labor Party today because he is the nominee of the trade union movement,’’ he said.
The proposed royal commission will be considered by the federal cabinet on Monday. The government has been building a public case for a Royal Commission for weeks.
It has already launched a Royal Commission into the botched home insulation scheme rolled out by the former Rudd government.
News Corp Australia reported on Sunday that former high Court judge John Dyson Heydon will lead the union inquiry.