Casual workers could soon have the right to become permanent employees, but business groups warn the changes may create economic uncertainty.

Employment Minister Tony Burke has unveiled changes to force bosses to offer casual staff who work regular hours a permanent job.

Workers would not have to take up the offer and could remain a casual employee to continue receiving loadings on their hourly rates.

More than 850,000 people will be covered by the changes, but Mr Burke expects most casuals won’t take them up.

He said the proposal would neither deter employers from taking on casual workers nor impact businesses’ bottom lines.

“I don’t see in a million years how this can add costs to business, because instead of paying the loading you pay leave, you never pay both … and they’re calculated to offset each other,” he said in Canberra on Monday.

“By giving people secure jobs you get a more loyal workforce and you get a workforce that appreciates the security that’s been given to them.

“That can only be good for business and productivity.”

Mr Burke said the changes would improve workers’ rights and close a loophole used by employers to avoid paying permanent entitlements to an ongoing workforce.

Businesses will not have to back-pay employees for any entitlements gained by moving to permanent employment.

“At the moment you can be working a full-time roster for a year and you still get classed as a casual,” Mr Burke said.

“There’ll be some people with those sorts of hours who want to stay where they are and nothing will change for them, but for people who want security this gives them a way to be able to do it.”

Australian Council of Commerce and Industry chief executive Andrew McKellar warned the changes could create uncertainty for businesses.

“Our most fundamental concern is that there is already very significant certainty here for business and for employees around the definition of casual employment,” he said.

“The government is seeking to unpick that certainty, it’s taking us back into uncharted waters.

“The risk is that will lead to greater cost for business and less certainty for employees.”

Australian Council of Trade Unions secretary Sally McManus said the government’s proposal was modest.

“People who are working regular jobs with regular hours deserve regular rights,” she said.

“The government is leaving it in the hands of the worker to decide, if they’re working regular hours, they want to be a permanent employee, get sick leave and annual leave or whether they want to keep their loading and remain as a casual.

“I don’t think that it could be fairer than that.”

– AAP