Almost three quarters of businesses on wage subsidies have used emergency workplace laws to change workers' hours, duties and location.
The Morrison government tasked management consultants Nous with examining whether the provisions were successful.
They surveyed 1810 employers accessing JobKeeper payments, with 73 per cent using at least one of the powers.
Reducing employees' hours or days was the most commonly used pandemic power.
More than 40 per cent of bosses surveyed directed workers to reduce hours, while 30 per cent changed or cut days.
Almost one-in-five asked employees to perform different duties and 17 per cent changed the work location, including switching to home.
Around 18 per cent directed workers to go on leave at full pay and three per cent at half pay.
Industrial Relations Minister Christian Porter said the powers were vital for businesses forced to close or suffering significant turnover reductions.
"The temporary JobKeeper IR provisions gave businesses that flexibility, enabling them to quickly adapt to changing conditions and stay connected to their workforce, ensuring they would be ready to bounce back when conditions improved," he said.
The research unearthed concerns in how the changes were invoked, with some employees asked to work more hours feeling considerable pressure to agree, even if it was difficult to accommodate.
All unions consulted argued for more explicit guidance on how to interpret and apply the measures.
Employee representatives also called for a wider view to be taken on what might be reasonable grounds for workers declining a request.
The survey found the number of disputes lodged with the Fair Work Commission was not unusually high.
More than 184 were heard before the commission or proceeded to conciliation or mediation.
Employers were supportive of the provisions, with between 84 and 98 per cent saying the measures helped them operate during the pandemic.
Treasurer Josh Frydenberg has flagged the government would like to see similar arrangements permanently adopted in the future.
Australian Associated Press
