Preschools and childcare centres in New South Wales may be given the legal right to refuse to enrol children who have not been vaccinated.
The state Opposition will present legislation to Parliament allowing the right of refusal following declining rates of vaccination that in some parts of NSW are now lower than in Rwanda.
Health authorities have warned that unless checked, the decline will threaten the measles-free status Australia achieved in 2005 and new epidemics would become inevitable.
"This is about preventing deaths in young children," shadow health minister Andrew McDonald said.
Although not yet endorsing the move, NSW's Liberal Government and Prime Minister Julia Gillard have backed the proposed legislation's aim of increasing child vaccination rates.
Authorities urge vaccination against a number of diseases including measles, mumps, rubella, whooping cough, rotavirus, hepatitis A, meningococcal disease, polio, and chicken pox.
The NSW move follows alarm in Britain, where an outbreak of rubella, known commonly as German measles, has so far infected 1300 people. More than 50,000 people have now been vaccinated against measles, mumps and rubella in an emergency programme, but 15,000 remain unprotected with low vaccination take-up rates among 10 to 18-year-olds.
In Australia, the National Health Performance Authority said 77,000 children were not fully immunised, with rates for 1 to 5-year-olds falling in some areas to 85 per cent or lower. The Australian Medical Association says rates below 93 per cent are "unsafe".
Pockets of affluence in major cities such as Sydney showed vaccination rates lower than the national average, reflecting international research showing that resistance to vaccination is stronger among people with higher education.
Opponents of vaccination argue that parents have the right to decide what is best for their children, and that vaccines can be unsafe and cause serious side-effects, weaken the immune system, and can cause autism. Health authorities reject the arguments.
In NSW Opposition leader John Robertson said the proposal to allow preschools and childcare centres the right to refuse enrolment to unvaccinated children would not infringe on parents' rights as alternatives would remain available. He said the right to refuse enrolment was important because parents who did not vaccinate were putting the lives of other children at risk. But most people who did not vaccinate their children were forgetful rather than opponents, who were still a small minority.