Prime Minister Anthony Albanese has pledged there will be no change to Western Australia's GST arrangements after a report recommended scrapping the existing deal.On his first visit to WA since an interim Productivity Commission report recommended the 2018 Morrison government GST arrangement be removed, Mr Albanese repeated the state deserved its "fair share".'What I believe is very clearly, there will be no change to WA's GST arrangements whilst I'm prime minister," he told reporters."That is my view. That has consistently been my view."The prime minister was pressed several times by Perth journalists on his promise and insisted: "There will be no change to WA's arrangements whatsoever on the GST."The Productivity Commission published its interim report into the GST carve up earlier this month, finding the 2018 WA GST deal was a "costly mistake" which had only benefited WA and should be scrapped.That deal assured WA would receive a 75 cent floor in each dollar of GST contributed, with top-up arrangements for other states to ensure none were left worse off.But the commission found this had cost the federal budget $23 billion in its first six years, $22 billion of which had flowed to WA.The release of the report sparked an angry rebuke from the west, with Premier Roger Cook brandishing the report's authors as "east-coast clowns".WA to get 'fair share'Mr Albanese, whose government endorsed and extended the Morrison-era deal to at least 2029, had subsequently said WA would "get its fair share" of GST.Mr Cook had said Mr Albanese told him over the phone WA's GST arrangements would not change.But the state opposition and the resources sector have been among those demanding Mr Albanese make that commitment publicly and explain what he means by "fair share"."The floor of 75 per cent will absolutely stay. I think WA deserves that because WA contributes to the national economy and helps to drive that economy," Mr Albanese said on Monday.He had a message for state premiers and chief ministers on the "no worse off guarantee"."An important thing that sometimes isn't understood from some of the critique of WA getting its fair share of the GST is that those additional payments have not come from states and territories. They have come from the Commonwealth," he said."I'm comfortable with that and what I say to premiers and chief ministers, though, is you need to bear that in mind when you are discussing federal-state financial relations."WA premier 'relieved'"I think every Western Australian is both relieved and pleased to hear the words from the prime minister today that Western Australia's arrangements for the GST will remain," Roger Cook said."We are very pleased that the prime minister has backed WA. As I've said before, he gets WA."Mr Cook said it finalises the debate.Anthony Albanese with Roger Cook in Henderson. (ABC News: Keane Bourke)"The prime minister has provided an assurance to Western Australians that Western Australia's arrangement for the GST will remain," he said.Mr Cook said WA would continue to fight for GST share in the lead up to the Productivity Commission's final report on the GST at the end of the year.Mr Albanese was in Henderson, in Perth's south, for an announcement on the AUKUS nuclear submarine deal with the United States and the United Kingdom.He declared a specific site in the centre of Henderson would be the location of a new defence precinct, which he described as a "major step" towards establishing a sovereign ship building and maintenance hub in WA."AUKUS is full steam ahead and WA is central to it," the prime minister said.