Prime Minister Anthony Albanese has assured West Australians the GST arrangements that have boosted the state budget by billions annually will remain unchanged while he is in the top job.

Roger Cook will use Anthony Albanese’s upcoming visit to seek assurances the state’s GST deal is safe after a blistering report branded it a “costly mistake”.

The state’s share of the GST has come under fire after the Productivity Commission released an interim report labelling the 2018 deal that guarantees WA a minimum return from…