Labor says Pauline Hanson has sold out Queensland by backing a bigger share of GST for Western Australia over her home state.
The One Nation leader, who was expected in Perth on Friday ahead of a state by-election, told the West Australian newspaper she supported her WA colleague Senator Peter Georgiou's call for a "better GST deal" for WA.
The federal government is due next week to release a report by the Productivity Commission into the GST carve-up between the states and territories, which could recommend changes to the existing formula.
Queensland Treasurer Jackie Trad, who released her state budget last week, has expressed fears the state could lose $1.6 billion under the proposed formula change.
But Senator Hanson believes she has a responsibility beyond Queensland.
"As a senator in this place, and you're making decisions on the floor of parliament, you have to step outside your state as well, and you've got to look at what is fair and balanced," Senator Hanson told the West Australian.
Labor leader Bill Shorten, campaigning on Friday in the Longman federal by-election in Queensland where One Nation is standing, said Senator Hanson had abandoned her state.
"Hanson, I understood, was the senator for Queensland - now she looks like she wants to be the senator for Western Australia," Mr Shorten said.
"The reality is people promising you can rob one state and give it to another state do no-one any favours - the best way to make sure states get their fair share is to properly manage the budget."
Treasurer Scott Morrison said the government would deliver a "fair" long-term plan to fix the GST carve-up for all states and territories.
WA's share of the GST shrank to less than 30 cents in the dollar due to the mining boom.
Mr Morrison said all the states understood the same thing could happen to them under the current arrangements, which made change crucial.
"You could have a land boom in NSW and that could have the same impact on the GST distribution as the mining boom had on WA - we genuinely do get it." he said.
On South Australian radio, Mr Morrison said state governments would be guaranteed funding for "essential services" under any changes.
WA Chamber of Commerce chief economist Rick Newnham said it was good to see senators from outside his state arguing in favour of a greater slice for WA.
"Queensland has a strong economy that its people can be proud of. There is simply no reason why a strong and proud state like Queensland must be subsidised to the extent it currently is by Western Australia, New South Wales and Victoria through the GST system," he said.
Australian Associated Press
