The Shop, Distributive and Allied Employees Association has lodged a Federal Court Claim in South Australia against 323 McDonald's operators and the multinational firm itself over the alleged denial of paid rest breaks at nearly 1000 current and former McDonald's sites.

The SDA is seeking $250 million in compensation plus penalties to cover roughly some 250,000 current and former McDonald's workers across Australia after it claims two years of investigating Fast Food Award breaches.

Under the award, all McDonald's workers are entitled to an uninterrupted 10-minute break when working four hours or more.

SDA South Australia Secretary Josh Peak said the landmark claim was needed to keep the international fast food chain accountable.

"Just because McDonald's is a multinational, multi-billion dollar fast food behemoth doesn't mean they can pick and choose which laws to follow," he said on Friday.

"These Federal Court claims are not just about compensation and penalising McDonald's, it's about sending a clear message that this systematic exploitation of young workers ... will not be tolerated".

A former McDonald's employee in Whyalla in South Australia named Brianna, who declined to use her surname, said she expected better treatment from her employer.

"When I was first trained, I was told that I wasn't allowed to take a paid drink or rest break because I can have a drink of water whenever I like," she said.

"It's pretty disappointing to know that my employer was withholding my entitlements and cutting corners when I was expected to follow the rules."

The new claim is in conjunction with the SDA's 15 existing Federal Court claims against McDonald's Australia and 14 franchisees nationwide.

Australian Associated Press