Ongoing production of XXXX beverages in Queensland is in doubt with staff being notified the brand's Brisbane brewery will close.
Management from Japanese controlled parent-company Lion notified staff in June the Castlemaine Perkins brewery in Milton would be shut down, United Voice coordinator Damien Davie told AAP.
Other workers had received threats the plant would close if negotiations to scrap full time jobs in favour of labour-hire, part-time and casual positions were unsuccessful, Mr Davie said.
"The continued push to bring in labour-hire employees and casualise the workforce is the main reason cited by management when threatening workers with closing the plant," he added.
"A large proportion of XXXX is now made at the Tooheys Brewery in Lidcombe, Western Sydney.
"XXXX gold is also made at West End in South Australia and in some circumstances even at the Boags Brewery in Tasmania."
Lion has been contacted for comment.
Doubts about the future location of the brand's production coincides with the end of its long term sponsorship of Queensland's State of Origin team after Wednesday's final 2017 game.