Canberra would not stand in the way of a rise in the goods and services tax if it came with compensation for taxpayers and help for the states and territories to abolish taxes such as stamp duty on house sales, Mr Barr said.

He was speaking during a debate in the ACT Parliament, in which the Liberals attacked the government over the big rates increases each year and the drawn-out timetable for the abolition of stamp duty.

Mr Barr said rates had increased every year since self-government.

"An increase in rates every year has been a given for as long as all of us have been alive," he said. "What has changed over the tax-reform process is that elements of additional rates increases have funded the abolition or reduction of three other taxes: insurance taxes, payroll taxes and stamp duties.

"And the benefits that have been delivered to businesses, particularly through the series of payroll tax cuts, amount to tens of millions of dollars annually."

The Labor government is into its fourth year of rates reform. It has increased rates by about 10 per cent a year. Tax insurance has been almost phased out, and payroll tax has been cut. Stamp duty has also been cut each year, but this year, Mr Barr has hinted at the possibility of a slowdown in the cuts to stamp duty, which might not be gone altogether in 2032 as originally planned.

On Wednesday, Mr Barr said stamp duty would continue to be cut in every budget in which he was Treasurer, with experts internationally and nationally agreeing on the need to get rid of the tax.

But the GST debate had added a new dimension to the pace of tax reform and might allow the timetable to be sped up, he said.

"If the Australian people vote for an increase in the GST, the Australian Senate passes a package that includes other offsetting tax cuts and those offsetting tax cuts include payments to the states and territories to abolish a range of inefficient state and territory taxes, then stamp duty may, in fact, be abolished in the ACT quicker than the two decades," he said.

"The ACT government would not use our intergovernmental powers to block such a reform if all of those preconditions were met," he said, referring to the Turnbull government taking the GST to the election, compensation through social security payments and income tax cuts, and measures to encourage states to abolish other taxes. "We will work with them."

Liberal leader Jeremy Hanson said while the Labor Party had flatly denied rates would triple under its tax changes, rates had already increased an average 42 per cent in four years, and at the current pace would triple in 11.7 years.

Canberrans had "struggled to believe the government would do something that was so cruel to so many families, to so many older people", but now they were getting their tax bills and saying "you guys were right", Mr Hanson said.