The chair of one of Australia’s largest companies has launched a broadside at proposed changes to industrial relations laws, saying they would result in fewer jobs and lower wages for workers.

Wesfarmers chairman Michael Chaney said the Albanese government’s “closing loopholes” bill would fundamentally rewrite Australia’s employment landscape for the worse.

He made the comments in Perth on Thursday at the annual general meeting of the conglomerate that owns Kmart and Bunnings.

“We are very concerned by many aspects of the bill,” Chaney told the meeting, adding that those concerns had only grown in recent months.

He said a proposed change to casual employment would introduce a new ambiguous definition, making it harder for companies such as Wesfarmers to offer casual work.

More than 50,000 of Wesfarmers’ 120,000 employees are casuals and Chaney said that when approached, the overwhelming majority choose to remain as such for the flexibility and higher rates.

The legislation would not force any worker to switch from casual status, it would be voluntary and up to the worker, but Chaney said the rules would still introduce complexity, uncertainty and cost.

“The administrative burden on employers of implementing and keeping up with the changes would inevitably lead to a reduction in job opportunities – casual and permanent – as businesses take steps to mitigate risks that would arise from these changes,” he said.

The government’s proposal would most affect young people still in education, working parents with caring responsibilities, team members with a disability and those easing into retirement, he said.

The Australian Council of Trade Unions has called for the bill to be enacted as soon as possible and criticised the coalition for pushing back its possible passage.

“Australia is in a wages emergency right now and in an emergency you don’t wait around, you act,” ACTU president Michele O’Neil said earlier in October.

“Workers are seeing their bills go up and up, yet their pay isn’t keeping pace.

“This is one bill workers will be pleased to see, one that creates more reliable, secure jobs in a cost-of-living crisis.”

Wesfarmers managing director Rob Scott told the meeting higher inflation and interest rates were continuing to impact customer demand.

“While consumers continue to demonstrate a degree of caution in making big-ticket purchases, demand for products that support necessary repair and maintenance and smaller-scale projects remains robust, and Bunnings has seen increased foot traffic to stores through the year to date,” he said.

Overall trading for the first 16 weeks of 2023-24 has continued generally in line with Wesfarmers’ results for 2022-23, he said.

Wesfarmers’ other businesses include Officeworks, Target, a chemical, energy and fertiliser business, an industrial health and safety division and a health business that includes the Priceline and Soul Pattinson pharmacy chains.

-AAP