A series of issues papers, setting out the key areas of the Commission's inquiry, were inadvertently published online ahead of an imposed embargo. The review was scheduled to be released at midnight on Friday but went live on Thursday morning. It was subsequently found by two Labor MPs, who then tweeted the link.
Other major areas to be reviewed are enterprise bargaining, individual agreements, unfair dismissal, anti-bullying laws and issues with public sector employment.
The review's findings, due out in November, will shape the Coalition's industrial relations policy for its second term, and is part of a pre-election promise from PM Tony Abbott.
Productivity Commission chairman Peter Harris said the issues papers were open to stakeholder comment until 13 March.
"We know people hold passionate views about workplace relations," he said.
"I'd like to emphasise that the commission is open-minded, and our approach will be evidence-based and impartial."
Waste of time and money
An ACTU spokesperson said since at least four inquiries are already underway examining aspects of workplace law, including a royal commission into union corruption, proceeding with a review of bills now was "a waste of taxpayer resources and the Senate's time".
"It is inevitable that the government will develop further legislation as a result of some or all of these inquiries, requiring the parliament to consider the matters again in 2016," ACTU secretary Dave Oliver said.
"It is bizarre for the government to be pursuing an extensive legislative program in perfect parallel to multi-million dollar review processes into the exact same subject matter."
'Shameless union ploy'
Business fired back at the union's statements, with Australian Chamber of Commerce Industry spokesman John Osborn saying the criticism was a "shameless and transparent ploy … to stall vital workplace reforms and protect their vested interests".
"Businesses are suffering right now. We can't afford to wait while new job and investment opportunities are being lost," Osborn said.
Likewise Ai Group said the timing for in-depth debate on IR reform was correct.
"Workplace relations reform shouldn't be a dirty word," the group's industrial relations direct Stephen Smith told reporters.
"We really need to look at what sorts of changes need to be made to give not only employers but employees the flexibility that 21st century workplaces need."