The West Australian economy has managed to stay in the black, but a deficit looms for the 2014/15 financial year.
The $239 million surplus for the year ended June 30 is just $2 million shy of the pre-election estimate in February.
But it is down sharply from $649 million for the previous period because of lower revenues from payroll tax, public utilities, the GST carve-up and iron ore royalties.
Treasurer Troy Buswell said easing economic growth reflected the transition from an intense construction phase in WA to a production phase as new mines come online, needing fewer staff.
The unemployment rate is tipped to rise to 5.5 per cent this financial year, from 4.4 per cent.
"Our economy is supported by ongoing work on a number of large liquefied natural gas and iron ore projects," Mr Buswell said.
"But the flow of new projects has eased and business investment in WA appears to have peaked, although still expected to stay at historically high levels.
"The government is attempting to achieve a difficult balance of investment in services and infrastructure to cope with spiralling demand from a growing population, while some traditionally strong revenue streams, like payroll tax and land tax, are not performing as strongly as previously expected."
A $386 million surplus has been forecast for the current financial year, which Mr Buswell describes as a modest buffer against the state's falling GST share and any commodity price falls.
An expected growth in revenue of 8.9 per cent in 2013/14 is attributed to an increase in the royalty rate for iron ore fines and drastic cost cutting in the public sector under the Liberal government's $6.8 billion "Fiscal Action Plan".
The state's books are predicted to slide into the red by $147 million in 2014/15, which Mr Buswell largely blames on falling GST revenue, and would come despite an expected steady increase in LNG and iron ore exports.
If WA's GST projections are to be believed, given they differ from those in the Commonwealth Budget Papers, the state's share will plunge from 4.9 per cent this financial year to 0.9 per cent in 2016/17.
And with a record spend on infrastructure ahead, debt is poised to soar well beyond the state government's previously hallowed $20 billion cap, rising to $28.3 billion in four years' time, from $18.5 billion at the end of June.
The Mr Buswell may well be kept awake at night worrying about retaining WA's AAA credit rating, with debt servicing costs set to soar from $46.6 million last financial year to $201.4 million in 2015/16.
