One of Australia's leading business lobby groups is urging crossbench senators not to pass any industrial relations changes if Parliament sits before the Senate changes over.

Key points: The Ai Group is concerned industrial relations changes may pass between the election and the Senate changing over on July 1

The Ai Group is concerned industrial relations changes may pass between the election and the Senate changing over on July 1 The lobby group is especially concerned about reversing the recent penalty rate cuts, labour hire regulation and criminal penalties for wage theft

The lobby group is especially concerned about reversing the recent penalty rate cuts, labour hire regulation and criminal penalties for wage theft The group's CEO Innes Willox has written a 14-page letter to current cross-bench senators

The Australian Industry Group fears the possibility that the next government, particularly if Labor wins the election, may try to hurry industrial relations changes through the existing Senate before senators elected in the May 18 vote take their places on July 1.

The possibility arises because while members of Parliament are sworn in once results are officially declared new senators will only commence their terms on July 1.

This means there may be a short period in June during which there is a new government in control of the House of Representatives while the current Senate remains in place.

That concern has prompted the Ai Group to write to the current crossbench senators, urging them not to pass any industrial relations changes during that period.

"There is a need for genuine consultation with industry about all the proposed changes to workplace relations laws before and after any legislation is drafted," Ai Group chief executive Innes Willox wrote in a 14-page letter.

"Many of the changes that have been proposed by one or both of the major parties would have major adverse impacts on businesses, employees and the broader labour market."

Ai Group wants penalty rate cuts to stay

One key issue of concern to the Ai Group is Labor's proposal to wind back Sunday and public holiday penalty rate cuts instituted by a ruling of the Fair Work Commission (FWC).

A recent analysis by the Australia Institute's Centre for Future Work found that the changes would cost employees in the affected retail, hospitality, accommodation and pharmacy sectors about $8 million on Sundays and $16 million on public holidays.

The centre said that, for example, affected employees working over the 10-day Easter-Anzac Day period — which many took off — were $80 million worse off than they would have been before the cut to penalty rates.

Mr Willox said he believed that Labor's commitment to rolling back the penalty rate cut within 100 days of taking office involved putting forward the Fair Work Amendment (Protecting Take-home Pay) Bill 2017, which would limit the FWC's ability to make any changes to awards likely to reduce the take-home pay of employees.

"What is the point in having an independent umpire if the umpire is only able to rule in favour of one of the parties?" Mr Willox asked rhetorically.

"The bill makes a mockery of the notion of having an independent tribunal to maintain awards."

The Ai Group has also expressed concerns about a number of changes recommended by the Government's Migrant Workers' Taskforce being considered by both the Coalition and Labor.

These include a national labour hire licensing scheme to regulate companies that provide workers, particularly in the horticulture, cleaning, security and meat processing industries.

Labor is proposing additional regulation that would require labour hire companies to provide wages and conditions no less favourable than the wages and conditions provided by the firms that are using their services to their own in-house employees.

"Taking away the flexibility that labour hire businesses and their clients need would reduce productivity, competitiveness and employment," Mr Willox warned the crossbench senators.

Criminal penalties 'would discourage investment'

The Ai Group is also arguing against another recommendation of the Migrant Workers' Taskforce, that criminal penalties should be introduced for serious and deliberate breaches of workplace laws.

Mr Willox warned that criminal proceedings would slow down the compensation of employees for back-pay they were owed and that there had already been a substantial increase in financial penalties for workplace law breaches.

"Implementing criminal penalties for wage underpayments would discourage investment, entrepreneurship and employment growth," he added.

The Ai Group has also expressed concerns about Labor's policy proposals to raise the minimum wage to a "living wage", tighten the definition of a casual employee, abolish the Australian Building and Construction Commission, make it more difficult for employers to unilaterally apply to terminate an expired enterprise agreement and introduce some degree of industry-wide bargaining in certain sectors.

Mr Willox said all of these significant industrial relations changes should first be considered by the relevant Senate committee, a ministerial consultative council with industry and unions, as well as discussed with state and territory governments.