Slavery laws must have penalties: lawyers

Laws to stamp out modern slavery in the supply chains of Australian businesses won't work unless there's appropriate penalties in place, law professionals believe.

A Senate inquiry is putting under the microscope draft federal government laws to make companies take action to stop modern slavery being connected with their business.

Law Council boss Morry Bailes wants to see financial penalties for non-compliance included in the laws.

"The lack of penalties in the legislation for non-compliance with the reporting requirements means there is little incentive or entities to report," he is set to tell the inquiry on Friday.

Mr Bailes will also call for a requirement that companies bidding for government contacts to be up to date with reporting where it's required.

The draft legislation would require companies with revenue above $100 million to report to the government, though the Law Council is also recommending that be reduced to $60 million.

At the very least the recommendations should be implemented when the legislation is reviewed after three years, Mr Bailes said.

He also called for the creation of an Anti-Slavery Commissioner - a proposal supported by the federal opposition.

"It's one of the most grave human rights abuses to take away someone's liberty, and I don't think it is too much to ask that Australian companies report on the things that they are doing to tackle this problem," Labor's justice spokesperson Clare O'Neil told ABC radio on Friday.

"It's not optional to abide by the law for anybody else in this country, and companies shouldn't be given any type of different or special treatment."

On Thursday supermarket giant Woolworths rejected calls from human rights groups to penalise businesses who don't show how they're stamping out slavery in supply chains.

Woolworths Group responsible sourcing manager Laura McManus said penalties wouldn't promote transparency in the private sector.