Thousands of taxi drivers, licence plate owners and operators have signed up to a class action against ride-share giant Uber.

More than 5500 entities affected across Australia have signed on to the suit, according to Maurice Blackburn lawyers.

Senior associate Elizabeth O'Shea said she had spoken to people who had bought a plate thinking it was a sound financial investment for their future, as well as drivers and operators.

"They've been devastated in this," Ms O'Shea said.

Some people had lost their retirement savings, gone bankrupt or had seen the value of businesses and licence plates drop dramatically.

The suit will claim Uber operated without complying with relevant legislation, as drivers lacked appropriate accreditation and weren't driving licensed vehicles.

"Some operators and drivers are looking at the prospect of working into their 70s to make up for their loss," Ms O'Shea said.

"It's a real injustice."

The deadline for people wanting to join the class action has been extended until April 29.

The case against Uber is set to be filed in the Victorian Supreme Court later this year.

Uber has been contacted for comment.

BREAKDOWN OF CLASS ACTION ENTITIES BY STATE:

* Victoria - 2036

* NSW - 1837

* Queensland - 1121

* WA - 539