Malcolm Turnbull has told coalition MPs the government's modelling shows raising the GST rate does not provide the economic benefits that advocates have assumed.
The prime minister briefed a joint partyroom meeting in Canberra on Tuesday on the government's tax reform work.
It was the responsibility of a "grown-up government" to examine tax and economic policy with great care.
"We have looked very painfully and carefully at the proposal to raise the GST and it does not proffer the economic benefits that many have assumed," Mr Turnbull said.
The first hurdle for changing the GST was its economic feasibility.
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The prime minister gave another example of the problems with tax reform, referring to states and territories switching from stamp duties to land taxes.
"You get 10 out of 10 from the economists for economic purity but it is 11 out of 10 for political difficulty," he said.
MPs were told further modelling was being done, including more work on the GST.
The final decision on the coalition's tax policy would be unveiled in the May budget, Mr Turnbull said.
One MP told the meeting the government should not take the knee-jerk step of ruling out a GST rise.
Mr Turnbull responded to the comment, saying the government was trying to grow the economy and revenues faster than government spending is growing.
