Italian prosecutors on Wednesday told Uber Eats and other food delivery platforms their couriers were employees and not independent workers, fining them 733 million euros for breach of labour safety rules.

The more than 60,000 couriers who worked for Uber Eats, Glovo, Just Eat and Deliveroo in Italy during 2017-2020 must be offered non-permanent contracts with fixed pay, the Milan prosecutors' office said in a statement.

"We can no longer consider riders as slaves, it is time for them to be considered as citizens who need legal protection," Milan chief prosecutor Francesco Greco said in a press conference.

The four companies should also pay past social security and insurance payments, prosecutors said. Prosecutors did not specify a sum but such a bill could easily reach hundreds of millions of euros.

In addition, couriers should be given "adequate" clothing, including helmets, gloves, reflective vests and anti-coronavirus face masks, as well as company bicycles or scooters, prosecutors said.

Companies were given 90 days to comply with the requests.

They were also ordered to pay fines totalling some 733 million euros ($900 million) to settle the labour safety issues with Italian authorities, a sum that could rise based on their other infractions.

An Uber spokesperson said the San Francisco-based company was committed to "raising the standard of work" and giving its workers more benefits, while preserving flexibility on how and when they work.

"Over the past months, we have put in place a landmark framework for stronger protections and more benefits for independent couriers in Italy, while working hard to set new standards for health and safety protection," Uber said.

Assodelivery, a trade group representing the four companies targeted, did not immediately respond to a request for comment.

Italy's largest trade union, CGIL, called the prosecutors' move "great news," saying couriers need to be protected by a national work contract.

The injunction strikes at the heart of the so-called gig economy, which relies on hundreds of thousands of independent workers for app-based services like food delivery or car rides.

Uber has long argued its business model provides flexibility and control to its workers, who can pick and choose when and how much they work, and has warned that fewer people would be hired were they considered employees.

But critics have argued that the company's refusal to consider their app-based workers as employees leads to low pay and a lack of medical insurance and other benefits.

The company won a major victory in November in its home state of California, when voters approved a ballot proposal by Uber that maintains gig workers as independent contractors, while offering some healthcare and minimum pay.

The European Union is currently considering the issue.

Most recently, on February 19, Britain's Supreme Court ruled that Uber drivers and delivery people are workers, and not independent contractors.