The AMA says allowing private insurers to cover GP visits would lead to a two-tier, US-style health care system.
Doctors fear private health insurers are making a concerted effort to undermine their profession.
They warn a push by insurers to cover primary care is a step towards a US-style health system.
The insurers are lobbying the federal government to allow them to enter the lucrative primary care market – services which are now covered by Medicare.
Health Minister Peter Dutton has said he is prepared to consider such a change because insurers could deliver savings to the government.
But Australian Medical Association president Brian Owler, in a speech to the National Press Club in Canberra on Wednesday, pointed to a controversial Medibank Private trial in Queensland where its members were being given priority in a small number of clinics.
“Those without insurance … will have less access to a GP,” he said.
“I fear a concerted effort on behalf of private health insurers to undermine and control the medical profession.”
Dr Owler also disputed government claims that Australia’s health spending was unsustainable.
Compared with other OECD countries it was lower than average, he said.
On the government’s controversial plan for a $7 GP co-payment, Dr Owler said the AMA was still working on an alternative proposal to take to the government.
Health couldn’t just be seen through the financial lens, he said.
“As a nation becomes more prosperous, its total expenditure on health care should increase – just as it should on education.”