Three vaccinated truck drivers have tested positive for COVID-19.

Two of the drivers arrived in WA from South Australia on Thursday.

They both returned negative COVID tests at the border  before being granted entry into the state.

The drivers spent three days in WA before returning to South Australia where they returned a positive test.

Health Minister Roger Cook says 55 contacts have been identified.

In a separate case two truck drivers arrived in WA from South Australia on Thursday and returned a negative test before being granted entry.

They spent 24 hours in WA, one driver tested positive once they returned to South Australia.

Exposure sites have been listed on the Healthy WA website and include businesses in Norseman, Coolgardie, Cannington, Kewdale and Bentley.