But it has drawn praise from the Liberals’ Commonwealth colleagues, with federal Treasurer Scott Morrison “welcoming” Weatherill’s contribution to the tax debate.

The Premier today rejected a scathing response from SA Unions to his proposal, detailed yesterday, which urged raising the GST rate from 10 to 15 per cent, with the Commonwealth to take the extra 5 per cent to compensate low income earners and use any remaining funds at its discretion. In return, the states would receive a fixed share of personal income tax receipts to replace a raft of Commonwealth grants.

In an unusually blunt critique of the Weatherill administration, SA Unions “absolutely rejected” the plan, with state secretary Joe Szakacs declaring it a “fundamental betrayal of working people”.

“Just 18 months ago – the day before the last state election – Premier Weatherill promised he would stand up to Canberra and their plan for a GST increase … today, he’s failed the people of SA,” said Szakacs.

He accused Weatherill of “trying to be a player on the national political stage and a spruiker of the Abbott-Turnbull GST agenda”, and suggested raising the rate would also lead to broadening the GST base to include food, an analysis the Premier rejects.

“We’re not talking about putting a GST on food or health or education,” Weatherill told FIVEaa today.

“All this is subject to the idea that low income earners would be fully compensated … I think you just need to sit back and look at the big picture.

“Healthcare expenditure is growing at a rate that State Governments just simply can’t sustain.”

He argues raising the GST alone “doesn’t solve the problem … because GST isn’t growing at the same rate of growth of our healthcare expenditure”.

“In the short term …it raises too much money, but in the long term it starts to erode and we’ll be back where we started from within a decade,” he said.

“So looking at things from the long term perspective, we’re in a bit of a stalemate at the moment. “

Opposition Leader Steven Marshall said the Premier’s proposal meant “every time South Australians open their wallet, Mr Weatherill will take more of their money”.

“Jay Weatherill wants to keep taxing people until they’re on their knees – I won’t stand for that,” he said.

“We need a fairer tax system that encourages economic growth and job creation – we actually need to be lowering taxes, not increasing them.”

But Morrison was positive, telling reporters today: “I really do welcome both (Weatherill’s) contribution and his treasurer (Tom Koutsantonis’s) contribution to this debate.”

“They are part of it – sadly their federal Labor colleagues have chosen not to be.”

On cue, federal Labor frontbencher Anthony Albanese told FIVEaa he and his colleagues “don’t support increasing the GST”.

“I think the premise of that is wrong because it’s a tax that impacts the hardest on the poorest people, because no matter what your income you pay the same amount of tax and therefore it’s a regressive tax,” he said.

“For all of those people who don’t pay any income tax now, I can’t see how you can compensate those people for an increase in their GST.”

Weatherill said he had briefed “everybody that I possibly could in the time I had available” before announcing his proposal, including “every State and Territory (leader) and also my Federal colleagues and as many of the substantial lobby groups as I could”.

“I think generally speaking people think it’s a constructive contribution to breaking the deadlock in the national debate,” he said.

“I’m open to any other ideas to solve this challenge…I just haven’t heard it yet.”