Both sides of federal politics have used appearances in Perth to promise WA will continue to receive its fair share of the GST, with Nationals leader Matt Canavan and the Prime Minister’s assistant minister Patrick Gorman committing to the current deal.

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 every dollar raised as a “mistake”.

Speaking at an event in WA’s capital, federal member for Perth and assistant minister to the Prime Minister Gorman said when it comes to the GST, WA is going to get a fair share.

“We have said that from day one, from when we were elected. I have campaigned on it at four elections. WA’s share of the GST is locked in, rock solid,” he said.

“The Prime Minister has not only guaranteed Western Australia getting our fair share and backed the WA GST deal - beyond that, five budgets we’ve delivered where that has been locked in and the money has flowed.”

Gorman, who was in Perth to spruik the Commonwealth’s announcement to invest $49 million in an additional 54 dwellings in WA for crisis and transitional accommodation, said the state has received record amounts of GST.

“I think [there will be] $9.3 billion of GST flowing to the state government this financial year,” he said.

“And that is because our government kept our commitment, our rock-solid commitment to WA of getting the legislated fair share of the GST.

“Like I said, I have fought for this at four elections, and every day that I am the federal member for Perth, WA is going to get a fair share of the GST.”

Canavan, who is in WA ahead of the National party’s state conference on Saturday, reminded the state that it was his side of politics that created the 2018 deal.

“Let’s be very clear that it was a Liberal and Nationals government in 2018 which solved this problem,” he said.

“It was a problem that had bedevilled government for years.

“We took that problem as a government, spent a long time dealing with it and thinking about it.

“There were numerous cabinet meetings going through all different types of options, and in my view, we came up with a deal that dealt with the injustice to WA, promoted resource development and productivity, and most importantly, kept our country together, kept the nation of Australia as one.”

Canavan called out other states for failing to make use of their natural resources, unlike WA’s commitment to the mining industry.

“I will highlight the insanity of New South Wales and Victoria locking up their gas reserves, not developing their own resources, and then turning around and saying other states that do that should not only give them their gas, give them their resources, but also give them their GST too,” Canavan said.

“Well, actually, what should happen in the first place, clearly here, is that all states and territories should seek to develop our country, and then we’d have an embarrassment of riches, and we wouldn’t have to argue over what is a shrinking pie under this Labor Party.”

Under the 2018 deal, WA is guaranteed a minimum return of 75 cents for every dollar of GST raised in the state, or a share no lower than the lowest distribution attributed to New South Wales or Victoria.

This means that if NSW receives 82c in the dollar and is below the amount Victoria earns – as it is in the current distribution – WA also earns the same.

According to Bankwest Curtin Economics Centre director Professor Alan Duncan, under a return to the pre-2018 deal, one of the options proposed by the Productivity Commission, WA could lose up to $6 billion per year in GST distribution.