The action at the PWCS will start both days at 8pm and stretch throughout the night shift until 4am.

It is being co-ordinated by the single bargaining unit, which represents workers from the Maritime Union of Australia, the Transport Workers Union, the Electrical Trade Union, and the Australian Manufacturing Workers Union.

MUA Newcastle branch secretary Glen Williams said: “PWCS continues to pursue an anti-union, anti-worker approach to these negotiations in the face of a wall of unity and solidarity.

“Well over 95% of the workforce voted in favour of industrial action to defend conditions of employment that have delivered a tripling in productivity and boundless flexibility in the business.

“The company needs to finally understand that these workers will not break. It’s time the company came back to the table and ceased its campaign to wind back the rights of its employees.”

Williams said that the unions and workers, while ready to take protected industrial action, continued to seek a negotiated agreement.

A spokesman for PWCS said the company continued to negotiate in good faith with the unions.

Williams said the unions sought a return to a co-operative and consultative approach to resolving disputes in the workplace.