THE Federal Government's plan to immunise the population against swine flu is in chaos because insurers may not cover doctors who administer the jab.

Inadequate testing and the possibility of spreading other infections means there is too high a risk patients will sue, the insurers say.

Despite weeks of crisis talks, the Government has refused to underwrite doctors' liability for the vaccinations and medical groups say the program - due to start as early as mid-September - cannot proceed unless doctors are insured.

The president of the Australian Medical Association, Andrew Pesce, said: ''The indemnity issue needs to be sorted out or else the vaccination program won't go ahead … In the environment we're in, someone has to be held accountable for rare vaccine reactions that may occur …

''If the Government decides there is a priority need to roll out the vaccine, then it has a duty to indemnify the doctors who provide it.''

A spokesman for the Royal Australian College of General Practitioners, Ronald McCoy, said the wrangling could undermine community confidence in the vaccine's safety. ''It's the public's health that's at risk here,'' he said.

The Health Minister, Nicola Roxon, announced in May an order with vaccine supplier CSL for 21 million doses - enough to protect at least half the population from the flu strain. Analysts' estimates suggest that contract may be worth up to $120 million.

But the insurers believe the distribution of the vaccine in multiple-dose vials exposes people to unnecessary risk of blood-borne infection from other recipients. As well, they believe the possibility of rare side-effects has been inadequately explored. These issues, they say, will make it hard for doctors to advise people whether or not to have the injection, exposing them to patient complaints that they were not properly informed.

The chief executive of the Medical Indemnity Industry Association of Australia, Ellen Edmonds-Wilson, said it was up to individual insurers ''to make an assessment of the risk [from] the drug'', which she noted had not yet been approved by the Therapeutic Goods Administration.

Medical defence organisations MDA National Insurance and Avant Mutual Group said they were still considering whether to indemnify members who gave patients the vaccinations. Avant's general manager of claims, Lisa Clarke, said the entire industry was ''in ongoing discussions with the [health department] on the proposed roll-out.''

A spokeswoman for the Medical Indemnity Protection Society, Elda Rebechi, said the company would cover doctors, but warned them to ''appropriately advise patients that the vaccine is untested and may have [currently] unknown consequences … We do not know the risk [or] benefit of the vaccine versus contracting the disease.''

But the head of clinical research at the National Centre for Immunisation Research and Surveillance at the University of Sydney, Robert Booy, said the insurers' arguments were superficial and ''unnecessarily inflammatory'', and proper training of clinicians would virtually eliminate infection risk.

Other doctors questioned the Government's commitment to multi-dose vials, saying they were ordered when experts feared a severe epidemic.

NSW emergency departments last week saw 203 patients with flu symptoms - down from 338 a week earlier, and a low number compared to regular flu seasons, NSW Health said yesterday.

CSL's director of public affairs, Rachel David, said the company's clinical trials were designed to test how much vaccine would be needed to provoke an immune response, not its fundamental safety - which was the same as seasonal flu vaccine.

A spokeswoman for the Department of Health and Ageing said the Government would take delivery of 2 million vaccine doses by the end of August. ''These can be predeployed and stored in states and territories in preparation for an initial vaccine program'', when further CSL trial data was received, she said.

Ms Roxon has said immunisations could start by mid-September, but the spokeswoman emphasised the start date was not set. The program would focus first on health workers, pregnant women and people with chronic disease. Children would receive the shots later.

The department was ''discussing medical indemnity issues for immunisation providers with relevant stakeholders''.