A union boss says Malcolm Turnbull "lied" to the governor-general in seeking a special sitting of parliament to deal with workplace laws.
Construction Forestry Mining and Energy Union national secretary Dave Noonan made the explosive claim during a debate on industrial laws at the National Press Club in Canberra on Wednesday.
"The election campaign has started with a lie told by the prime minister," Mr Noonan said.
On Monday, Sir Peter Cosgrove accepted Mr Turnbull's advice to bring back parliament on April 18 to deal with a bill to restore the Australian Building and Construction Commission.
If the bill fails, Mr Turnbull will call a double-dissolution election for July 2.
Mr Turnbull's written advice to Sir Peter Cosgrove said the legislation was of great importance "to deal with widespread and systemic criminality in the building and construction industry".
But Mr Noonan said the ABCC had no power to deal with criminality, but rather would enforce workplace laws which are backed up by civil penalties.
He added the recent Heydon royal commission had not recommended the ABCC be set up, but rather called for stronger penalties for misconduct across the whole economy.
Mr Noonan said Mr Turnbull was more intent on throwing "red meat to the zoo animals" - referring to conservative MPs within the coalition such as Eric Abetz and former prime minister Tony Abbott - than improving the economy and productivity.
Australian Industry Group chief Innes Willox, who took part in the debate, said the ABCC was essential to restoring law and order in the construction industry and improving productivity.
Mr Willox quoted Justice Dyson Heydon who said in his report that the union movement had room for "louts, thugs, bullies, thieves, perjurers, those who threaten violence ... and organisers of boycotts".
"We would see a return of more employment opportunities, better job security and the opportunity for higher wages if we had an appropriately balanced workplace relations policy," he said.
He said the ABCC was just one aspect of what was needed.
Other policies should include restricting unions' right of entry to workplaces, limiting the number of discussion points in enterprise bargaining and better transfer-of-business laws.
Mr Willox admitted industrial disputes were at a "low level", but the economy was facing "choppy waters" and the industrial relations pendulum should be returned to the centre after having swung too far to the left under the Labor government.
Comment was being sought from Mr Turnbull.
