Opposition assistant spokesman for health Stephen Jones and Cunningham MP Sharon Bird claim the four-year Medicare rebate freeze is simply the latest version of the ‘‘GP tax’’ and further evidence of the government’s ‘‘chaotic handling of health policy’’.

The opposition MPs say research by the University of Sydney, published in the Medical Journal of Australia in April, revealed the rebate freeze could cost patients about $8.40 more by 2018 – higher than the original GP co-payment.

The revelation came after Prime Minister Tony Abbott and Health Minister Sussan Ley scrapped the GP co-payment in March amid public backlash.

At the time, Mr Jones told the Mercury he was worried the rebate freeze would ‘‘fly under the radar and have a greater impact on people than the GP tax’’.

On Wednesday, the Throsby MP said the ‘‘GP tax by stealth’’ would have a particularly profound impact on those who could least afford it.

‘‘The researchers from the University of Sydney found that the freeze will have a ‘greater impact on practices that serve socio-economically disadvantaged populations’,’’ he said.

‘‘What it means in practice is that many people with recurring problems such as chronic disease will avoid seeing their local doctor, worsening existing conditions and lead to overcrowding in our hospital waiting rooms.

‘‘The rebate freeze confirms Tony Abbott’s promise that the GP tax is dead is as believable as his promises before the election of no new taxes and no cuts to health. He can’t be trusted.’’

Ms Bird said the rebate freeze would impose an up-front charge between Illawarra patients and their GP, ‘‘destroying Medicare’s universal health care’’.

‘‘The Abbott government is committed to forcing down bulk-billing by making more patients pay to see a doctor,’’ she said.

Ms Ley said it was clear Labor’s “year of no idea” in health continued.

‘‘The only health policy we have seen from Labor to date is a plan to cut the health budget – no area exempt. That means Medicare, hospitals and medicines,’’ Ms Ley said.

‘‘This government is working constructively with health professionals to deliver a healthier Medicare ...’’