The Maritime Union of Australia has confirmed its members plan to strike for three days at Esperance Port next week.
About 80 stevedores will walk off the job in three consecutive 24-hour stoppages scheduled to begin on Wednesday.
Union organiser Jeff Cassar said both the union and the Esperance Ports Sea and Land (EPSL) board had come to a wages deal, but the board had backed down at the eleventh hour.
“The port met with us earlier this month and put to us a proposal which was effectively a compromise,” he said. “In the interest in avoiding a dispute, the membership accepted it and we had a deal in principle. On Tuesday, we met with the port again and they informed us that the proposal they had put on the table failed to get approval.”