They joined ACTU President Michelle O'Neil and occupational lung disease specialist Dr Chris Clarke to call on Senate crossbenchers to block the passage of the Ensuring Integrity Bill, saying it would leave workers vulnerable to employers like James Hardie.

James Hardie Industries was a major asbestos manufacturer in Australia and ignored the health risks of handling asbestos for years, before stopping production and paying out many workers compensation after union lobbying.

"The Ensuring Integrity Bill - whoever dreamed that up needs a gold Logie. It's more like Ensuring Inequity in my opinion," said Jim Iverson, who was recently diagnosed with asbestosis after suffering from symptoms for almost 20 years.

Dr Clarke said the union movement was valuable in terms of ensuring workplace health and safety.

"If anyone needs reminder of what they've done, one need look at the asbestos campaign that took place ... to try and achieve justice for people with this condition," Dr Clarke said.

Industrial Relations Minister Christian Porter told question time claims by the ACTU and sufferers are "simply an incorrect contention".

He said the laws were aimed at stopping "the most serious, repetitive law-breaking" within the union movement.

The government's chances of passing the bill have been boosted by Tasmanian senator Jacqui Lambie's swing vote ultimatum for John Setka to resign.

Australian Associated Press