Malcolm Turnbull's new Employment Minister, Michaelia Cash, is already experienced in wrestling with unions.

Before she entered politics in 2008, Senator Cash worked in Perth as an industrial lawyer for the national law firm Freehills.

More recently, as the then assistant minister for immigration and border protection, Senator Cash, 45, battled with the union movement during a review of the integrity of 457 working visas for foreigners.

Unions criticised her for not going far enough to restrict foreign labour and the exploitation of vulnerable workers. She criticised them for running a "fraudulent campaign".

Last month, she accused industrial organisations including the Maritime Union of Australia and the Transport Workers Union of hypocrisy in hiring at least 41 people holding 457 visas over the past five years.

Earlier this month, she lashed out at Opposition Leader Bill Shorten for siding with the militant Construction, Forestry, Mining and Energy Union which had "spun a web of lies about labour market testing under the China-Australia free trade agreement".

Former ACTU assistant secretary Tim Lyons said unions were "entitled to be extremely worried" that Senator Cash had worked for a law firm identified with anti-union actions.

Mr Lyons said he expected that Senator Cash would likely enjoy some goodwill in Parliament from crossbenchers who failed to support outgoing employment minister Eric Abetz pass any legislation including the Fair Work Amendment Bill and legislation to reintroduce the Australian Building and Construction Commission.

"It's pretty remarkable that he didn't manage to get a single piece of legislation through. The one thing Abetz had going from him from a union perspective was that he wasn't effective," Mr Lyons said.

In 2013, Senator Cash - who has also been named Minister for Women in the new ministry -  gave a speech in which she said true cultural change in the workplace in relation to gender equality would only occur when it was driven by employers.

"This government does not believe in legislated quotas," she said. "We will, however, support employers in every effort they make to reach the voluntary targets set by them to ensure gender equality in the workplace."

She said she was lucky to see an innovative program for supporting women into leadership at Freehills in 2004.

"By the time I left the firm in 2008, a target of 20 per cent of female partners had been reached," she said.

Senator Cash will be under pressure from business groups to deliver cuts to penalty rates and negotiate changes to the Fair Work Act, to be put to a Senate vote next month.

Australian Chamber of Commerce and Industry chief executive officer Kate Carnell welcomed her appointment and said she looked forward to her "deploying her strong advocacy skills to put the case for improvements to our workplace relations system, including engaging seriously with the recommendations that emerge from the Productivity Commission inquiry into the matter".

Wilhelm Harnisch, the chief executive officer of Master Builders Australia also welcomed the appointment of Senator Cash to pursue industrial relations reform, a major driver of productivity growth. He said restoration of the Australian Building and Construction Commission was an "essential priority for the building and construction industry".

"Master Builders therefore welcomes the appointment of Senator ... Michaelia Cash as Minister for Employment to continue the government's pursuit of this vital reform," Mr Harnisch said.

Community and Public Sector Union national secretary Nadine Flood said Minister Cash was taking on a portfolio where the loss of 17,000 jobs has added to the pressure on public services.

"This new ministry, and Minister Cash's past experience in the field of industrial relations, provides an opportunity for rethinking the government's failed bargaining policy and instead taking a modern, productive approach to public sector workplace relations," Ms Flood said.

"Meeting the growth, reform and service delivery challenges facing government will require a fundamentally different approach to the public sector."

ACTU president Ged Kearney also congratulated Senator Cash on her appointment and said she looked forward to the opportunity "to begin a meaningful dialogue with her on the issues that matter to workers and their families".

Ms Kearney said she will write and request a meeting with Senator Cash to discuss the protection and creation of local jobs for all Australians through investment in local industries, such as ship building and manufacturing. She would also request protection of workers' rights and a stop to attacks on penalty rates, the minimum wage and other family-friendly rights such as paid parental leave.

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