Cutting penalty rates across the country has failed to create any extra jobs or give workers more hours, new research has found.

In a blow to the Turnbull government's backing of the Fair Work Commission's decision to reduce penalty rates, a survey of 1351 workers by the University of Wollongong and Macquarie University found there has been no short-term increase in average weekly hours worked by employees.

University of Wollongong lecturer Dr Martin O'Brien.

Fair Work justified its decision in March by arguing a gradual reduction in penalty rates would result in more trading hours, an expansion in the level of services offered and an increase in overall hours worked.

But University of Wollongong lecturer Martin O'Brien will tell the Western Economic Association International conference in January that some workers actually experienced a drop in the number of penalty-rate hours they worked in the first two months after they were reduced.