When WA Labor strategists hunt for material for the next state election to argue they are superior financial managers to the Liberal Opposition, they won't need to look far.

The typically bland-in-language credit rating agency, Moody's, handed the McGowan Government the sort of praise a WA administration has not seen in years as the state moved a step closer to regaining a sought-after AAA credit rating this week.

The decision to upgrade WA's credit rating from AA2 to the second-best possible rating of AA1 "recognises the strong fiscal resolve of the State Government", Moody's said, adding budget recovery had been "underpinned by tight control over recurrent expenditure".

Moody's was far from the only body glowing in its assessment of Premier Mark McGowan and Treasurer Ben Wyatt.

"The Premier and the Treasurer deserve congratulations, it is their leadership that has led us to this place," Chamber of Commerce and Industry chief executive Chris Rodwell said.

Alan Duncan, director of the Bankwest Curtin Economics Centre, joined in on social media, labelling the efforts of Mr McGowan and Mr Wyatt "a fine public finance lesson".

A lone voice of criticism

Opposition Leader Mike Nahan also lavished praise following Moody's announcement, but his was pointed in a different direction.

"West Australians have Scott Morrison's Government to thank for the upgrade in credit rating," Dr Nahan said.

"The credit rating happened not because of, but in spite of, Mark McGowan."

Opposition Leader Mike Nahan maintains WA is succeeding in spite of the Government. ( ABC News: Andrew O'Connor )

Dr Nahan's Opposition has spent much of the past two and a half years attacking the State Government's economic and financial credentials, a cause that has been helped by both data and anecdotal evidence that WA's economy continues to struggle.

Falling house prices, scores of high-profile hospitality closures in key suburban strips, unemployment that reached record levels earlier this year and figures this week that showed WA's domestic economy was still shrinking have all given the Liberals ammunition that Labor has mismanaged the economy.

Turning economic tide blunts the barbs

But even some of the most ardent Liberals would likely accept that arguing they are superior financial managers to WA Labor has become trickier in recent weeks.

WA's budget is back in the black, with multi-billion dollar surpluses on the horizon. The state's massive debt bill is expected to finally stop growing soon.

And, after the Liberals were in charge while WA's credit rating was downgraded twice, Labor has now overseen an upgrade.

But despite the latest batch of good budget news for the state, Dr Nahan has made it clear the Liberals will not shy away from attacking the Government's economic and financial record.

"Mark McGowan was elected on creating jobs and he has failed," the Opposition Leader said.

"The economy is the worst I have seen it since the 1990s recession that we had to have."

Dr Nahan's use of the "recession" label this week earned a sharp rebuke from Mr Wyatt, who accused the Opposition Leader of recklessly talking down the economy.

"For a political leader like Mike Nahan to be running around saying 'recession' is grossly irresponsible," Mr Wyatt said.

He maintained there were positive signs for the broader economy, such as an improving mining sector.

The state election is still more than 18 months away, but already some of the battlelines are becoming clear.

The Liberal Party will tell voters Labor has failed on its pledge to create jobs and fix the economy, so cannot be trusted to turn the state around.

But Labor will be able to point to some big surpluses, an improved credit rating and some high praise from money boffins — as well as the former Liberal government's record of multi-billion-dollar deficits — as it tries to convince voters to leave it in charge of WA for another four years.