Treasurer Ben Wyatt on Thursday handed down his fourth budget, defying the global economic gloom by predicting a $1.2 billion surplus this financial year driven by a resurgent iron ore price.

Big-ticket items include a promise to hire an additional 800 police officers over the next four years and a previously-announced $600 credit towards every WA household's power bills.

But public servants will be disappointed after the government ruled out a wage hike beyond the current freeze.

The finances are forecast to remain in the black over four years but an estimated $6.6 billion will be shaved from the surpluses projected last December.

An $18 billion net debt blowout is set to almost double the state's borrowings to $43 billion.

"Responding to the COVID-19 pandemic has been the toughest challenge we have faced," Mr Wyatt told parliament in his budget speech.

"We should be proud of the fact that our state has not only recorded some of the lowest rates of COVID-19 in the world, but also that our economy has fared much better than most."

WA's unemployment rate is forecast to climb to eight per cent by next June but jobs growth is forecast in each of the following years.

The budget models a second wave of COVID-19 outbreaks under which $5.6 billion and 30,000 jobs would be lost from the economy.

Like the federal budget, it's assumed WA's hard borders will reopen from April 1 - after the March state election - but Mr Wyatt cautioned that it was only a projection.

"It would have a very benign impact on the assumptions," he told reporters.

Most of the infrastructure spend will be on road and rail projects, including the government's signature Metronet train network extension.

A plunge in overall government revenue has been countered by the surging iron ore price.

Currently tracking around $US120 per tonne, it is tipped to remain well above the long-run average in coming months.

Mr Wyatt said WA's decision to prioritise removing restrictions ahead of reopening borders had ensured its financial position was better than forecast at the height of the pandemic.

More than $7 billion of the promised infrastructure blitz will be spent in regional WA as Labor seeks to consolidate its pole position ahead of the state election.

After being urged by the state and federal Liberals to spend big rather than banking a surplus, Mr Wyatt promised "every cent" of the surplus positions would go towards infrastructure spending rather than paying down debt.

"It's not about how much you spend, it's how you spend it," he said.

He said public sector wage increases would remain frozen at $1000 per year for the next two years before reverting to inflation.

Opposition treasury spokesman Dean Nalder labelled the budget "insipid".

"The fact that WA Labor would run a surplus at a time when so many small businesses and households are suffering is appalling," Mr Nalder said.

"Very little has been revealed today that has not already been announced."

Social organisations broadly welcomed the budget but the Chamber of Commerce and Industry said it was a missed opportunity to pursue tax reforms.

Australian Medical Association WA president Andrew Miller accused the government of failing to address health workforce shortages.

"It is ridiculous, quite frankly," he said.

"It takes more than police to manage a COVID pandemic."

Australian Associated Press