Australia's largest employer of young workers has been accused of denying them the paid breaks they were entitled to, with separate legal action launched by two unions.
McDonald's Australia recently marked its 50th anniversary, celebrating 1.5 million jobs it says it's created during that time.
But a number of its workers have accused the company of denying them paid 10-minute breaks they are entitled to take every four hours.
The Shop, Distributive and Allied Employees Association (SDA) is seeking compensation for workers who did not receive paid breaks, as well as penalties against McDonald's Australia for breaching the Fair Work Act.
"The fact that one of the largest employers of young Australians (on junior rates of pay) has been deliberately and systematically denying teenagers their breaks is astonishing," SDA national secretary Gerard Dwyer said.
The union's inquiries among McDonald's workers uncovered a number of alleged breaches, including through social media ads informing employees of their rights and encouraging them to contact the union if they were not receiving entitlements.
The SDA amended ongoing actions against McDonald's franchisees last month to include McDonald's Australia, which it accuses of conspiring to deny workers breaks and aiding and abetting franchisees to do so.
The legal action has been launched in the Federal Court in South Australia and the SDA says it could result in millions in compensation for thousands of workers around the country.
Many workers were allegedly told the paid break entitlements did not apply to them because they were allowed to drink or go to the bathroom throughout their shift, while others were informed their restaurant did not have enough staff to cover break periods.
McDonald's Australia senior corporate relations manager Samantha Brown told AAP the SDA claim was "both surprising and disappointing" and said the company intended defending itself to the fullest.
The company "believes its restaurants complied with applicable instruments, provided rest breaks to employees and were consistent with historic working arrangements", she said.
The SDA also did not challenge how breaks are taken or raise it as a matter of concern "throughout successive enterprise bargaining processes for new industrial agreements".
"We are very mindful of our obligations under applicable employment laws ... and continue to work closely with our restaurants to ensure employees receive all correct workplace entitlements and pay," Ms Brown said.
SDA SA branch secretary Josh Peak says McDonald's has fed workers a "cock and bull story about their break entitlements for too long".
"Fast food restaurants are busy, hot and the work is exhausting - it's shameful to think young workers have been denied their rightful breaks and told they don't exist."
The SDA action comes after the rival Retail and Fast Food Workers Union launched a separate class action with Shine Lawyers last month, following one of its members receiving $1800 compensation after legal action against a McDonald's franchisee that denied them paid breaks.
The SDA says its action differs as it is not a class action and the union will "represent hundreds of workers directly".
