Cadbury parent company Mondelez will appeal in the High Court against a Federal Court decision that granted Hobart shift workers greater leave entitlements.
The appeal announcement came just days after industry groups - including the Tasmanian Chamber of Commerce and Industry - met with federal Attorney-General Christian Porter to raise concerns about the decision.
The Federal Court found that workers who work 12-hour shifts should be entitled to greater leave as they lose more hours if they take a personal leave day, and that Mondelez's argument "places too much emphasis upon the monetary value of paid personal/carer's leave".
The court analysed the meaning of "10 days of paid personal/carer's leave" in the Fair Work Act, and whether this meant 10 calendar days or 10 blocks of 7.6 hours.
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The federal government intervened during the proceedings and made a submission that had "overlap" with the Mondelez submission.
The Australian Industry Group welcomed Mondelez's decision to appeal.
"The decision is inconsistent with widespread industry practice and it is essential that the decision is reviewed by the High Court," the Ai Group said in a statement.
"In addition to the cost impacts, the decision would impose a major barrier to employers agreeing to part-time employment arrangements, including for employees returning from parental leave.
"On the Federal Court's interpretation, a part-time employee who work one day a week would be entitled to the equivalent of 10 weeks of personal/carer's leave a year."
Mr Porter said the ruling was "relevant to every business where shifts are worked" and blamed Labor for the wording of the Fair Work Act.
The US-based multinational confectionery giant took Tasmanian employees Natasha Triffitt and Brendon McCormack, and the Australian Manufacturing Workers Union, to court over a clause in their 2017 agreement.
Justices ruled 2-1 in favour of the workers, finding "each employee will be equally protected against his or her loss of earnings".
The AMWU described the High Court appeal as the government "once again siding with their big business mates".
"This is a shameful attack on the shift workers who deserve the same 10 days of sick leave as every other worker," the AMWU wrote on social media.
"We'll be fighting this every step of the way."