The government can reduce health expenditure by rectifying "piecemeal" reform and investing in treating more people in the community, the Greens say.
The party was responding to a proposal received by the National Commission of Audit for a co-payment scheme for GP consultations.
Acting Greens leader Richard Di Natale, who will chair a senate committee established to report on the commission of audit, said for the government to "balance the books" on the back of the health care of ordinary Australians would be a "big mistake".
"Of course there are some efficiencies to be gained in health care but putting a barrier in front of people to access a doctor is not the way to achieve it," Senator Di Natale said on Wednesday.
Senator Di Natale said instead of a co-charge to see a doctor, the commission of audit should look at the health system more broadly.
"Why not look at those areas in health care we might be funding that are not being funded on the basis of good evidence," he said.
"We treat people in hospitals, often the worst places for somebody who's sick who doesn't need to be there, when we could be treating them in the community.
"We could be investing in the greater use of antibiotics, for example, in the community; greater supports for people in the community so that they're not in hospitals being exposed to the risk of infection."
