Tasmania will fight the prime minister's plan to change how the GST is carved up, with the state's Liberal government standing firm against its federal counterparts.
Liberal Premier Will Hodgman said there has always been ongoing threat that larger mainland states will swallow up Tasmania's GST share, and says he will fight for the state's entitlements.
"Our position has been consistent - we don't support any changes to the GST, full stop," Mr Hodgman told AAP in a statement on Sunday.
"Tasmanians can be confident that just like we stood up for Tasmania previously and defeated proposed changes to the GST distribution method, GST rate, and the state income tax proposal, we will fight and defeat this latest proposal too," he said.
Mr Turnbull announced at the WA Liberal state conference he'd work with premiers to put in a floor to how low a state's share of the GST could fall, after WA's take sharply dropped to an unusually low 30-odd cents back for every dollar it generated in recent years.
Tasmanian Opposition Leader Bryan Green argued Malcolm Turnbull was looking to punish the state for voting out three Liberal MPs at the recent federal election.
"Malcolm Turnbull is planning to give more to WA and that means Tasmania will be the loser," Mr Green said in a statement on Sunday, adding the southernmost state could lose "tens of millions of GST dollars".
He said Western Australia's Liberal government had "wasted billions of dollars in mineral royalties from the mining boom and ran up huge debts in recent years ... (and) they are now demanding more money from Canberra".
The federal government said a gradual phase-in would mean no other state would be disadvantaged because they wouldn't lose compared to the projected GST share over that time.
Mr Hodgman is the only Liberal state premier in the country to oppose the changes.
WA Premier Colin Barnett said he is delighted with the plan, expecting it to provide long-term security and stability in revenue.
