Western Australia is getting a slightly bigger slice of GST revenue this year but to call it a windfall is "ludicrous" and reform is still needed, the state treasurer says.
WA's share will jump from 34 to 47.3 cents for every GST dollar collected in 2018-19, which is about $140 million more than expected, but Treasurer Ben Wyatt says it still falls well short of helping to solve the state's budget woes.
"Any suggestion that an increase in GST relativity ... is a windfall, it's just ludicrous," he told reporters.
"Clearly it's a better outcome than we were otherwise budgeting for, but only slightly.
"We are still receiving less than half the GST that West Australians pay."
Before the Commonwealth Grants Commission even released its recommended relativities, Mr Wyatt foreshadowed other states might complain about receiving less than they expected.
He and WA Opposition Leader Mike Nahan remain in agreement that the GST system needs reform.
But Mr Wyatt said he had also talked to Senator Mathias Cormann and Federal Treasurer Scott Morrison about other financial contributions the commonwealth could make to WA infrastructure projects in the meantime.
"I hope in their commonwealth budget they're able to accommodate some of our infrastructure priorities, particularly around Metronet," he said.
Mr Wyatt said the small increase in GST would not change his budget strategy, which was aimed at reducing ongoing expense growth over the forward estimates.
Dr Nahan said the state government had not been counting on a $1 billion "windfall" over the next four years and now had no excuse to raise taxes or saddle households with higher electricity and water fees in the May budget.
He said most of the extra cash should go towards reducing the state's debt and deficit.
"This is a real test for them - what they do with it," he told reporters.
