The mining state's unemployment rate fell to 3.8 per cent during the month, from 4.1 per cent in March.
The result is more than a full percentage point below the national rate of 4.9 per cent and that of the next best performing state, New South Wales, WA Commerce Minister Simon O'Brien said.
Mr O'Brien said 48,700 jobs were created in WA in the past 12 months.
Premier Colin Barnett said the figures were further proof of the strength of the state's economy.
"On the national front, while the unemployment rate has fallen slightly, I still remain concerned about job losses we're seeing on the east coast, but in Western Australia it's a very good environment," Mr Barnett said.
Chamber of Commerce and Industry WA chief economist Dana Mason said growth continued to be uneven across industries, with resources and resources-related sectors performing strongly, but small businesses and consumer-related companies were suffering from low consumer confidence.
About half of the chamber's members had reported difficulty in sourcing labour, and the shortage of skilled staff was expected to continue for the next few years, she said.
Ms Mason said falling productivity remained a problem nationwide.
"It's certainly an issue that will need to be addressed if we are going to continue to record improvements in standards of living across the country," she said.
"It's really about looking at improving the supply-side capacity of the economy to respond to the strong demand that we're seeing."
Investment in infrastructure was one way capacity-building could be achieved, and CCI WA was disappointed that the state received only 10 per cent of infrastructure funding in the federal budget this week.
"It's really important to recognise that what's good for WA is good for the nation as well," Ms Mason said.
(Source: WA Business News)