At a time when both sides of federal politics have byelections on the brain, the Turnbull government will be enjoying a modest morale boost after the Liberals' clear victory in a Labor-held state seat in Western Australia on Saturday.

After falling to Labor with the rout of Colin Barnett's government in March 2017, the Perth fringe seat of Darling Range returned to the Liberal fold after a swing of nearly 10% to Liberal candidate Alyssa Hayden, a former state upper house MP who unexpectedly lost her seat at the state election to One Nation.