The Port Waratah Coal Services action will begin at 11pm and stretch throughout the night shift until 3am.
It is being coordinated by the single bargaining unit representing workers from the Maritime Union of Australia, the Transport Workers Union, the Electrical Trade Union, and the Australian Manufacturing Workers Union.
Despite the continued action, MUA national assistance secretary Ian Bray said an agreement was close.
“However, there remain a few unresolved issues that the workers consider important enough not to walk away from and, as a result, the workers are taking this protected industrial action.
“We emphasize again, however, that we seek to reach agreement on those unresolved matters because we, like PWCS, would welcome a return to getting on with the business of shipping coal to PWCS clients.”
Talks between union members and PWCS have seen more than nine months of negotiations.
A spokesman for PWCS told ILN during the last action two weeks ago that the port continued to negotiate in good faith with the unions.
The unions have said the continued strikes are because of their perceived unwillingness of PWCS to reach agreement on the major outstanding enterprise agreement issues.