"We won't accept any cut to penalty rates. Penalty rates need to be secured, they need to be put beyond doubt." Opposition Leader Bill Shorten during a visit to Backwell IXL in Geelong. Credit:Alex Ellinghausen Electrical Trades Union national secretary Allen Hicks also backed protecting penalty rates in legislation. "When we work overtime, weekends, unsocial hours and public holidays we should be justly compensated with penalty rates," he said. "Conservative politicians and business owners are trying to take money out of our pockets and there is every reason in the world to make a law to stop them."

The AMWU is politically close to Labor left faction leader Senator Kim Carr, who, in turn, is a key supporter of Mr Shorten. Further underscoring the politically fraught issue of penalty rates, Fairfax Media also contacted the Australian Workers Union - which Mr Shorten used to lead - the Shop Assistant's union, the Community and Public Sector Union, the Construction, Forestry, Mining and Energy union, the Rail, Tram and Bus union, the Transport Workers Union, the National Union of Workers and the Maritime Workers union for comment over penalty rates. None of these eight unions would comment on the issue. Australian Services Union deputy national secretary Linda White backed the Labor leader over not legislating penalty rates, telling Fairfax Media that "people who work unsociable hours should have penalty rates and that should be enshrined in safest way possible". "If I was an employee I don't know if I would trust my penalty rates to the vagaries of the political process."

At present, penalty rates are set by the independent Fair Work Commission, which is due to rule after the election on whether Sunday rates should be cut and brought into line with Saturday penalty rates. When pressed on Monday to guarantee there would be no cuts to penalty rates if elected, Mr Shorten said only that Labor "can be trusted to protect our penalty rates system". He highlighted a Labor submission to the commission to protect penalty rates and repeated a pledge to "further intervene in the case before the [Fair Work Commission] decision, to strengthen only as a government submission can, the case to defend our penalty rates". "I do also just caution the Greens, from their sideshow position, that they need to be careful of that [legislating to protect penalty rates], they're playing with fire by proposing that a government should be able to legislate on specific penalty rate outcomes, they are loading the gun for a future Conservative government to pull the trigger, because what the government has the power to put in, a future government has the power to dismantle," he said. "I'm a believer in the independent umpire to help set the terms and conditions and take it away from the politicians."

The comments are consistent with Mr Shorten's confirmation last month that "I'll accept the independent tribunal" ruling on penalty rates - but they leave the door open to penalty rates being cut by the Fair Work Commission under a Shorten Labor government. In a train-wreck interview earlier on Monday, Labor's workplace relations spokesman Brendan O'Connor repeatedly refused to guarantee weekend penalty rates would not be cut under a Shorten government, despite the opposition making the issue a key part of its campaign strategy, instead offering that "the umpire makes these decisions" and that "Labor is the party of penalty rates". Mr O'Connor said the ALP would await the final decision of the the independent industrial umpire, declined to say "yes" when asked seven times whether he supported Mr Shorten's past statements on the issue backing the independence of the umpire. Follow us on Twitter