Workplace innovation, including the Airtasker and Uber business models, risk the loss of hard-won protections for workers and the creation a new "hungry mile" in Australia, a leading law professor warns.

Joellen Riley, dean of the University of Sydney law school and professor of labour law, said she welcomed innovation in workplace but warned it came with risks.

"Without a thoughtful system of regulation, we leave everything up to the dog-eat-dog world and some people become serious losers and that's not good for society," she said.

It had taken 100 years to ensure the poorest people were working for reasonable wages and conditions and it was important these gains were not lost in new ways of engaging workers.