The growing practice of unpaid work for graduates is fostering concerns about a culture of dodgy student work placements in Australia.

Two young former interns said they were trying to raise awareness about the growing number of unscrupulous unpaid internships.

When she started her degree, Sydney law student Marie Iskander did a full-time unpaid internship with a private company.

"I was doing work that should have been paid," she said.

"At the end of the internship they offered a paid job for $8.00 an hour. I could have worked at McDonald's and got paid more."

Ms Iskander is also a member of the Australian Law Students' Association, a group concerned about a growing number of law graduates working for free.

She said because there was an oversupply of graduates in many fields, young people were willing to do unpaid work to get ahead.

"Basically [private companies] are offering them free work, and they're profiting from the free work," Ms Iskander said.

On many jobs sites in Australia, companies post advertisements for internships offering a chance to get "a competitive edge" or "hands-on experience".

Melbourne woman and former intern Colleen Chen said those unpaid internships were often unregulated and illegal, requiring students to work long hours for nothing.

"A lot of these ads could very easily be understood to be regular job ads. It's just that it's called an internship and it's unpaid," she said.

Ms Chen helped form the organisation Interns Australia after she did a 12-week placement at a publishing company, and was offered no workplace insurance.

"I soon realised that I wouldn't be covered by workplace safety covers if I were injured," she said.

Professor Andrew Stewart from the University of Adelaide wrote a report on unpaid internships for the Fair Work Ombudsman.

"What we've seen in the last few years is an increasing number of arrangements operating outside of formal education or training," he said.

"Businesses increasingly — some businesses — see an advantage in using someone to do unpaid work that previously they would have to pay an employee to do."

The Fair Work Ombudsman told PM it had seen a rise in calls relating to unpaid work this year.

But Ms Chen said most students were not coming forward with complaints for fear of losing their placements.

"It is highly unlikely for them to speak up because they don't want to burn their bridges," she said.