Unions have vowed to mobilise tens of thousands of members and to revive a militant WorkChoices-style campaign, as Prime Minister Tony Abbott signals industrial relations will be a key election battleground.

Political battles of the Howard era could reignite after confirmation a major inquiry will examine potential workplace relations reforms such as lowering the minimum wage and allowing employers to set their own penalty rates.

"The union movement will mobilise against these cuts," said Victorian Trades Hall secretary Luke Hilakari.

"This is WorkChoices 2.0 – it has nothing to do with improving the working lives of millions of Australians; it's about cutting people's wages and conditions."

The newly released Productivity Commission papers also flag an examination of whether the minimum wage should be varied by state or by region and possible changes to enterprise bargaining, individual agreements and unfair dismissal laws.

Mr Abbott has moved to reassure voters, saying "we might seek a broader mandate at the next election but certainly we are going to act within our mandate in this term".

And in comments that will provoke the ire of organised labour, he said penalty rates may be holding employers back from hiring more staff and opening at certain times.

"If you don't want to work on  a weekend, fair enough, don't work on a weekend, but if you do want to work on a weekend and lots of people, particularly young people, particularly students, would love to work on the weekend, you want to see the employers open to provide jobs," he said.

Industrial law expert Andrew Stewart said the review was always going to be a short-term fix to address criticism from the business lobby, but would deliver long-term political pain for the Abbott government.

"There are only going to be winners and losers from this inquiry and the government is likely to be loser from this, no matter what," he said.

Nurses and hospitality workers, two groups who are required to work outside normal hours, have lashed out at the review.

Aasha Sinha, who has worked as a bartender for the past decade, said that without penalty rates she and her colleagues would have struggled to cover the cost of living.

"Without the loading on a Saturday or a Sunday shift, many people would be up shit creek," said the 27-year-old from Woolloomooloo.

Ms Sinha said she has missed countless weddings, birthdays and a family Christmas, in order to work the unsociable hours that her job requires.

"It is a part of the job, but we should at least be compensated for it," she said. "It's pretty tough if you are only getting paid $17 an hour to deal with smashed customers on public holidays like Australia Day."

But Restaurant and Catering Association chief executive John Hart said one-third of restaurant and catering businesses did not trade on Sundays due to high wages.

Nurses in the state's hospitals are gearing up for union action should the commission recommend a review of their conditions.

Annie Butler, the acting federal secretary of the Australian Nursing and Midwifery Foundation, said that any changes to penalty rates "would have a devastating effect on the nurses in our industry".

"People don't stop being sick on weekends, people don't stop having babies on weekends," she said. "Nurses and midwifes will become extremely agitated if there are any threats to penalty rates, they make up to 40 per cent of their income from those hours."

Newtown nurse Ollie De Dear said that she got into the industry so she could help people.

"But without penalty rates a lot of people who might be thinking of going into nursing may just think it is too hard," the 24-year-old said.

Labor leader Bill Shorten said the review was part of the Abbott government's clear "agenda" to attack pay and conditions.