The strike is already in contravention of one back to work order from the Australian Industrial Relations Commission (AIRC) while employer, CBI Constructors has gone back to the AIRC seeking a further injunction.

The Australian Manufacturing Workers Union claims a supervisor manhandled a worker and has now called for the man to be sacked while the AIRC has called for an investigation into the incident.

The workers will also join a national action tomorrow calling for more local workers to be employed on big resources projects. The action includes a rally on the streets of Perth, which is expected to draw 5,000 unionists.

The peninsula has already struggled to attract the degree of expected international investment and development with chemical giant Methanex being the latest company to pull out of a multi-billion dollar project.