Workers rallies have shut down city centres across the country, sending public transport into chaos and blocking roads to thousands of motorists.

Change the Rules rally, a protest calling for better working conditions and a national pay rise, has been held in Sydney, Melbourne, Adelaide, Cairns, Townsville, Darwin and Wollongong.

In Melbourne it began at 10.30am at Trades Hall, crawled through major CBD streets.

Protesters were calling for wages to keep up with the cost of living. (AAP)

Today's protest was technically illegal. (AAP)

The ACTU says four out of five workers aren’t receiving pay rises in line with the cost of living, driving many into poverty. (AAP)

Up to 160,000 signed up to march in the rally, which closed parts of Lygon, Victoria and Swanston streets.

Protesters accused Prime Minister Scott Morrison of taking workers on a "highway to hell".

"We are fighting for our lives and a fair go," cleaner Rajita told reporters outside Trades Hall in Carlton before an AC/DC cover band performed for the crowd.

(Nine)

Trams are operating with limited service in Melbourne. (Nine)

Protesters have accused the PM of taking workers on a "highway to hell." (AAP)

ACTU secretary Sally McManus said the disruption was worth it.

"Our standard of living is going backwards. That should not be happening," ACTU secretary Sally McManus said in Melbourne.

"A small disruption for a couple of hours is worth it.

"There is an appalling figure that 28,000 working people are homeless in our country.

"That's because the minimum wage in our country is just $37,000 - that is not enough to support yourself."

The rally in Sydney was 10,000 workers strong. (AAP)

The protesters walked along Russell and La Trobe Streets before making their way down Swanston Street to Flinders Street Station.

Four out of five workers aren't receiving pay rises in line with the cost of living. (AAP)

Trams operated with limited service in the city, with most stopping at the edge of the CBD until the delays cleared just after 12.30pm.

The city circle tram was impacted as well as trams that operate along Bourke, Swanston, Collins and La Trobe streets.

Trains service in the city loop are running as normal and passengers were urged to use this as an alternative.

Extra staff were placed at tram spots and train stations around the CBD to help passengers.

VicRoads advised motorists to plan for delays and if possible to avoid to area all together.

In Sydney, the ACTU President Michele O’Neil addressed a crowd of around 10,000 who gathered at Belmore Park.

The protesters are calling on the Morrison government to bring back penalty rates. (AAP)

The procession marched down Pitt street, Bathurst Street and Castlereagh street just after midday.

The union says four out of five workers aren’t receiving pay rises in line with the cost of living, driving many into poverty.

As the rally prepared to get underway in Melbourne, CFMEU boss John Setka quoted historical figures in a tweet to justify the action, including Martin Luther King saying 'Never forget that everything Hitler did in Germany was legal,'.

Federal minister Kelly O'Dwyer accused him of comparing Hitler's Nazi Germany to Australia and said the comparison was "vile".

"John Setka has done it again. His vile slur against the Federal Govt (sic) likening it to the Hitler regime is beyond repugnant," she tweeted.

Premier Daniel Andrews planned to join the march, saying Victorians are working harder than ever but not being rewarded.

"They want a better deal, they're entitled to that, so they can provide the best for their kids and they can have a better standard of living and greater opportunities than their parents have had," he told reporters.

The Australian Chamber of Commerce and Industry has dismissed the union claims.

A similar rally earlier this year brought the CBD to a crawl with protesters walking along the roads. (AAP)

"Scratch the surface and the ACTU's campaign is really about putting power into the hands of big unions, disempowering employees, and removing their choices," CEO James Pearson said.

With AAP.