Australians could be slugged up to 15 per cent extra for a trip to the doctor if states follow through on a new payroll tax interpretation.
Royal Australian College of General Practitioners Vice President and Queensland Chair, Dr Bruce Willett, says updated rulings of existing payroll laws are poised to heap further pressure on the ailing bulk-billing network.
"This is not a Queensland issue. This is basically a whole-of-country issue," he told AAP on Sunday.
"All of the states have an agreement where they co-ordinate the application of payroll tax. The problems actually started in NSW and Victoria, who have been the most aggressive chasing payroll tax."
Dr Willett said the Queensland government has been co-operating on changes to payroll tax laws following separate rulings in Victoria and NSW.
Previously, medical practices did not pay payroll tax for tenant doctors as they were considered contractors and their wage was not included as part of the overall business.
"That's been the arrangement for 30 years and that's all been hunky dory," he said.
"What's happened is, particularly in NSW and Victoria, (governments) have taken a very aggressive view and deemed that to be a employee/employer relationship."
It effectively means practices with tenant doctors will have to pay payroll tax on 100 per cent of what they bill moving forward.
In Queensland, businesses which pay $6.5 million or less a year in taxable wages are subject to a payroll tax rate of 4.75 per cent.
The rate rises to 4.95 per cent for businesses with annual taxable wages above $6.5 million.
Dr Willett said the former rate was more than the profit margin for most practices, meaning they won't be able to absorb the change without passing on the cost to patients.
As a result, he expects out-of-pocket fees to increase by about 15 per cent as GPs will still feel obliged to bulk bill some patients but not others.
Queensland's Shadow Treasurer David Janetzki said the "new tax" would have serious consequences for the state's residents.
"This new stealth tax will drive up patient fees and emergency department presentations and drive down bulk billing," he said.
But unlike other states, the Queensland Revenue Office has pledged not to backdate payroll tax bills for affected clinics, agreeing to limit audits to the 2021/2022 financial year and beyond.
Queensland Transport Minister Mark Bailey disputed the payroll tax ruling would lead to higher doctor fees for patients.
"The state government revenue people do not specifically target the health sector at all, whereas in other states I know that they do," he told reporters in Greenbank on Sunday.
"This is a payroll tax level that is the lowest in the country and we need reform in the GP sector at a federal level after a decade of neglect. I think some of the accusations were inaccurate this morning."
He branded a report in The Courier-Mail a "beat-up" and said the Albanese government was working to address issues in the primary care network, including a well-publicised shortage of bulk-billing appointments.
Victorian Premier Daniel Andrews and NSW counterpart Dominic Perrottet have been publicly lobbying for national cabinet to make reforming the sector its number one priority this year.
National cabinet is next scheduled to meet on February 1.