A federal government backbencher says the tax debate has got to be about more than just a "lazy" hike in the GST.
The ongoing debate over tax reform rolled into Canberra on Monday as politicians returned for a four-day parliamentary sitting week.
A higher GST rate and broadening its base have drawn the most attention of any flagged tax changes.
But Liberal MP Angus Taylor says the discussion has got to be wider.
"We don't want to start this debate by talking about a lazy GST tax hike," he told reporters.
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Treasurer Scott Morrison insists the government has not nominated any specific changes, and so far only the states, some retired premiers and the odd backbencher has talked about changing the GST.
He reiterated the government was not trying to raise more revenue to balance the budget.
"It's about trying to grow the economy, and (trying) to lift the burden off people that have an income tax system which is punishing them," he told Sydney's 2GB radio.
Cabinet minister Simon Birmingham said the government won't be "spooked" by Labor's scare campaign on the GST.
Colleague Barnaby Joyce said any changes to the GST were a matter for the states.
"If the states want extra revenue ... then they have to lead the charge," he said.
Mr Morrison is hoping to meet with the states and territories before the end of the year to talk about state taxes.
Liberal MP Dan Tehan wants the government to consider applying GST to financial services, an idea previously raised by South Australian Premier Jay Weatherill.
Removing the existing exemption would generate at least $18 billion over the next four years, helping offset a reduction in the company tax rate. But Labor senator Doug Cameron said a decrease in company tax would just give "fat cat executives" salary increases.
Liberal Democrat senator David Leyonhjelm sees merit in broadening the GST to cover fresh food, saying there is no justification for it to apply to frozen vegetables but not fresh vegetables.
"Nutritionally there's no difference," he said.
