More than half of Australia's young adults have done unpaid work as part of an internship or a job trial, raising questions about the need for greater regulation of unpaid work to prevent exploitation, a landmark national study has found.

The study of 3800 people aged 18 to 29 from across the country is the first to investigate the prevalence of unpaid work in Australia and suggests it is becoming a pervasive norm in an increasingly competitive labour market.

Unpaid work experience now extends beyond traditional student placements in medicine, nursing and teaching to all areas across the workforce, including law, finance, creative arts, retail and hospitality.

The study findings have been released as the federal government prepares to introduce 120,000 internship placements over four years from this year as part of its Youth Jobs PaTH youth employment program. The University of Sydney is also planning to make work experience compulsory for all undergraduate students from next year.