Federal opposition leader Bill Shorten agrees Western Australia is not getting its fair share of the nation's GST revenue but will not commit yet to lifting it if elected.
WA will get just 34.4 cents in the dollar of GST this year.
Despite both Mr Shorten and Prime Minister Malcolm Turnbull having described that as too low, the man responsible for recommending the figure, Commonwealth Grants Commission secretary Michael Willcock, this week said it was fair.
A per-capita distribution would deliver about $6.7 billion, but it is only getting $2.3 billion this year under the complex formula that is intended to provide "equalisation" in states' abilities to provide government services but increasingly regarded as highly flawed.
"I get that Western Australia is not getting their fair share ... I'm here listening, what we will do is come up with concrete proposals after we've spoken with business, we've spoken with West Australian leaders and we will do that sooner rather than later," Mr Shorten told reporters at a press conference with Premier Mark McGowan.
"No doubt when you hear that figure of 34 cents in the dollar, how can that make sense?
"I don't want to see any state disadvantaged, but no doubt Western Australia is not getting its fair share of support from the Commonwealth."
Mr McGowan has proposed one solution to a new Productivity Commission review of the GST, calling for 25 per cent of WA's iron ore royalties to be quarantined from the GST carve-up to boost the state's share.
Mr McGowan said the process of producing the WA budget in September would be "very, very difficult".
WA has lost $2 billion in forecast projected revenue since Labor was elected in March, including less iron ore royalties revenue, less GST and Commonwealth health and education funding, while dealing with a record $3 billion deficit and record debt tipped to reach $42 billion.
