Mermaid Marine employees will carry out strike action at their Dampier Supply Base.
Thirty workers will carry out two 24 hour work stoppages following a breakdown in ongoing negotiations for a new enterprise agreement.
The first stoppage will occur from 6am Friday, 22 July and the second from 6am Monday 25 July.
Employees also have initiated a ban on all overtime work at the Dampier site for an indefinite period.
Mermaid say the work stoppages will not effect its slipway or vessel operations.
It went on to say that it will continue discussions over a new enterprise agreement.
Mermaid Marine supply marine services to the offshore oil and gas industry.