Unions have outlined a radical proposal to "change the rules", which they claim will ensure greater job security and better pay.

Australian Council of Trade Unions secretary Sally McManus addressed the National Press Club in Canberra on Wednesday, in what the peak body has dubbed the most important speech by a union leader in a generation.

The ACTU is calling for a clear definition of casual work which it believes should be limited.

"Casual employees who have worked on a regular basis for six months, deserve the right to choose to convert to permanent work," Ms McManus said.

SCLC secretary Arthur Rorris said too many people in workplaces across the country were forced to work as casuals, or similar.

As such, they were “excluded from basic rights and benefits” such as permanency and sick leave, Mr Rorris said.

“These are denied to a growing part of the Australian workforce and it’s in regional areas, such as the Illawarra and the South Coast where it is being felt the hardest,” he said.

Ending the uncapped temporary working visa program, an overhaul of labour hire and a shift in federal procurement rules will form part of the union's push.

Ms McManus wants to create a national labour hire licensing system to ensure companies do not cut wages and conditions.

Temporary visas must have strong protections against abuse and only be used for genuine shortages, she said.

Read more: 'It’s now a national issue’: ACTU boss praises Wollongong workers

The ACTU’s wishlist comes after it launched a major advertising campaign to “change the rules” last week and follows a visit by Ms McManus to Wollongong in September.

At the time, she praised the bravery of young Wollongong workers for lifting the lid on widespread exploitation and wage theft, and for making it a national issue. 

Mr Rorris said the pendulum had to swing “away from big business” and towards the interests of workers.

“If this continues, the casualisation and other trends, which attack wages and conditions, will spread through the entire workforce,” he said.

“That is not a hypothetical, it is the current trend and it will become unstoppable unless we change the rules.”

Workplace Minister Craig Laundy said the union's campaign was based on a lie and the rate of insecure work was the same as it was 20 years ago.

"This is a left-wing lunatic attempt to reset their business model," he told ABC radio, pointing out union membership had dropped to nine per cent of private sector workers.

"Casual work is a completely appropriate way for many businesses and many employees to conduct their relationship."       

– with AAP