FedEx has been accused of betraying its workforce as staff go on strike to protest pay and conditions.
Monday's strike comes after FedEx workers deferred action planned for last Thursday, when StarTrack workers walked off the job in a similar dispute with their own employer.
Transport Workers' Union national secretary Michael Kaine said the workers held off industrial action in good faith and came to the bargaining table to hear what FedEx offered.
"The offer was not an offer at all, it was a betrayal," he said on Monday.
Workers were due to negotiate a pay rise with the US-based parcel delivery giant last year, but Mr Kaine said they held off to see how the pandemic effected their industry and employer.
"It became very clear quite quickly what the effect on FedEx was, clients and customers boomed, they fuelled $US74 billion in FedEx revenue, $US5 billion in profit."
Mr Kaine said the company's decision not to give a pay rise was reprehensible and effectively amounted to stealing a wage increase from 2020 "that workers so responsibly deferred at the start of this pandemic to make sure the economy is right, that the sector is right and that FedEx is good to go".
He said FedEx, along with the government-owned StarTrack were now outliers in road transport after new agreements were reached with other companies like Linfox and Toll, accusing the federal government of being "missing in action" and criticising the "Americanisation" of industrial relations.
A FedEx spokeswoman said the strike could not come at a worse time for Australian businesses coming out of lockdown and customers would be adversely impacted.
The company had addressed the union's primary concern of job security and made concessions to resolve approximately 90 per cent of the union's claims, she said.
TWU state secretary for Queensland and NSW Richard Olsen said FedEx showed "a clear misunderstanding of where we're at with our negotiations".
"We need them to admit they made the wrong call last week and come back to the table ... what we're finding is a change in ownership ... now everything is purely about a dollar and not job security, our work is being outsourced to people who are unable to negotiate proper pay and conditions," Mr Olsen said.
FedEx acquired TNT in 2016 and rebranded in Australia earlier this year.
Tony Matthews, an owner-driver who is unable to participate in industrial action but who is on leave for a shoulder injury, attended a strike to show his support and said there were "very deep" feelings of anger.
"In good faith we expected them to acknowledge the (wage increase) deferment and come to the table, they've just said that didn't matter," Mr Matthews said.
Monday's strike is the latest in the past few months for the parcel delivery industry, which has seen companies and workers at loggerheads over conditions and outsourcing.
StarTrack workers went on strike on Thursday for the second time in a month.
Australians are already facing longer than usual wait times for parcel deliveries, with the sector buckling under the pressure caused by a spike in online shopping amid months of lockdown.
An industry-wide strike planned for last week was avoided after deals were reached at Toll, Linfox, Global Express and BevChain.
Australian Associated Press