The world's top union leader, Sharan Burrow, said wage theft in Australia was among the worst she'd seen in the world as she called for "serious sanctions" to prevent worker exploitation.

Geneva-based Ms Burrow, who travelled to Canberra on Thursday to receive her Companion of the Order of Australia and lobby the Senate crossbench to vote against the government's union-busting bill, said the level of wage theft in her home country was "unbelievable".

Sharan Burrow says wage theft in Australia is "unbelievable". Credit:Wayne Taylor

"Frankly, until you see some serious sanctions on people who engage in taking money from workers, then it is in fact a form of wage slavery and again it's unbelievable that it happens right here in Australia where you have a robust rule of law," the International Trade Union Confederation's general secretary said.

"The theft of wages in this country is akin to the kind of conditions we see in countries like the Gulf states where the kafala system [of migrant workers] exists."