A former maintenance worker in Gippsland will take a stand against big business as he and fellow "modern-day heroes of the trade union movement" march in Melbourne.
Troy Carter, 42, will take to the streets in support of workers' rights after claiming he was sacked by ExxonMobil's contractor UGL for refusing a pay cut and unfavourable roster.
"We attempted to negotiate for two years and they put out five offers we would not accept below what we were on. They terminated our jobs and the next day offered them back on (lower) terms," he told AAP.
"It is disgusting behaviour from companies that make billions of dollars."
He'll be joined by fellow sacked workers, the Electrical Trades Union and the Australian Manufacturing Workers Union as he marches to ExxonMobil headquarters to protest 230 job maintenance job cuts after union delegates meet at the Melbourne Town Hall on Tuesday.
Thousands of workers are expected to take part in union-led Change the Rules rallies being held across the country from Newcastle to Darwin over two weeks until May 18.
It is the biggest campaign since the "Your Rights at Work" effort in 2007 which helped bring down Work Choices and the Howard government.
The Australian Council of Trade Unions wants workers to have the right to take industrial action as a last resort rather than be fined or unions sued, and many of the rallies coincide with May Day events.
The ACTU is still waiting for the Fair Work Commission's decision on the latest minimum wage increase, which would take effect from July 1.