Elective surgery is likely to be disrupted at public hospitals in Western Australia as thousands of support workers including cleaners and orderlies take industrial action.

The work-to-rule campaign imposed from 6am (WST) on Monday involves about 8000 workers protesting over a stalled wages claim with WA's Health Department.

The Liquor, Hospitality and Miscellaneous Union (LHMU) is pushing for a pay rise of about $50 a week but says the department's pay offer of 8.25 per cent over three years would see workers only get $19.

Union secretary Dave Kelly said most of the members taking industrial action earned less than $40,000 a year and faced steep electricity and water bill increases imposed by the WA government.

"Our members are just trying to send a message to the government today that they need to come back with a more realistic pay offer.