This means the minimum full time wage in the state will increase to $665.90 per week from July 1.
All state award wage rates will also increase by $20 per week.
The decision comes after last week’s three per cent increase to the national minimum wage by the Fair Work Commission to $640.90 per week.
Unions WA secretary Meredith Hammat said decent minimum wages and award pay put a floor beneath growing inequality, which was a big problem in WA.
Hammat said the decision clashed with the WA premier Colin Barnett’s comment on Tuesday that he had spoken briefly to Attorney General Michael Mischin about remedying a situation where small businesses were disadvantaged by award structures.
Barnett said small businesses should be able to do the same as larger employers, such as Coles and Woolworths, which often negotiated enterprise agreements with unions to compensate lower weekend and night penalty rates with higher hourly rates during the week.
“A cut to weekend pay is just a pay cut,” Hammat said.
“Weekend and after hours pay help to protect particularly low paid and vulnerable workers from long, unsociable hours of work intruding on time with family, in study or in the community.”
But Barnett asked why people with a second job or students working part time over a weekend got dramatically higher rates than people whose whole career was working in the retail or hospitality sector, for instance.