Employees at Newcastle steel-maker InfraBuild will walk of the job from midday today, as they call for a fairer pay deal.
The action involves members of the Australian Workers' Union (AWU), the Australian Manufacturing Workers' Union (AMWU), and the Electrical Trades Union (ETU.
Members at both the Rod and AusTube Mills say the company's wage offer fails to keep pace with the cost of living, and low staffing levels have been affecting the morale of workers.
They also say management has moved them from a 12-hour shift pattern to an 8-hour one, and has taken away paid shower time and break provisions.
Organiser, Ben Horan from the Newcastle Branch of the AWU, says they are currently negotiating two InfraBuild enterprise agreements, which both expired in August.
"There has been some movement from the company which is encouraging...but we're just coming to a sticking point at the moment around wages and trying to keep our members up with the cost of living," he said.
The action will run for two hours, however Mr. Horan says they'll keep fighting if they have to.
"Moving forward, we're going to be absolutely ramping it up a lot more, with minimum 12-hour stoppages and things of that nature."
The industrial action marks the first time there have been strikes at the mills in 30 years.