WA is in line for a $1 billion boost to Treasury coffers next year as the State’s GST share continues to recover and the size of the national revenue pool grows above expectations.

The Commonwealth Grants Commission will today reveal that WA’s relativity payment will be lifted from 34¢ to 47¢ in the dollar in 2018-19, an $885 million increase compared with this year, and about $140 million more than the $3.1 billion budgeted when the payment was forecast at 45¢.

And in another unexpected bonus, WA is set to receive an extra $122 million as a result of the growing national GST pool, giving Treasurer Ben Wyatt about $260 million more than expected ahead of next month’s budget.

Despite the fiscal windfall, Mr Wyatt will still argue that the States should embrace wholesale GST reform, saying the upward revision to the GST payment after three years lagging below 35¢ would still leave WA short-changed.

Speaking before today’s Council of Federal Financial Relations meeting in Melbourne, Mr Wyatt said there was still a strong case for wholesale reform of how the GST was allocated and called for States to support the Productivity Commission review into the formula.

“That is very important because that is really the main device to try to convince the other States about the need for reform,” he said.

Ahead of today’s meeting, MPs in Tasmania and South Australia argued against a change to the GST formula, with Tasmanian Labor MP Julie Collins saying “billions of dollars” were at risk for her State.

“Western Australian Liberals are again calling for changes to the GST distribution and the Treasurer Scott Morrison must come clean and assure Tas-manians it won’t be at our expense,” she said.

Finance Minister Mathias Cormann said the Federal Government would help the State financially until the Productivity Commission handed down its report into the GST formula next month.

“We recognise that WA’s share of the GST is still too low, which is why we continue to work with the State Government on appropriate short-term measures to address this.”