A South Coast GP has warned that doctors can't afford to sit on the fence when it comes to immunisation and have a responsibility to speak up against "conspiracy theorists".
Dr Neil Donovan said the community was starting to see for itself "the effect on the ground" of people refusing to vaccinate their children.
"The whooping cough outbreak we had in our local community was such an example," Dr Donovan said.
"There was more disease because some families were not immunised."
The Berry GP said the public had a responsibility to increase "herd" immunity, with the risk of disease easily outweighing the risks of vaccination.
"If you provide a counter argument, it is because you are looking at diseases that are now rare and remain rare because everyone steps up," he said.
Measles, which had largely disappeared in Australia, has reappeared, with Wollongong and western Sydney identified as hot spots.
"The scourge of measles is once again raising its head locally," Dr Donovan said. "This is not a minor disease. It causes encephalitis in one in every 1000 children."
Across NSW, there have been more than 140 cases reported so far this year, compared to 26 cases in 2010.
Dr Donovan said he understood the instinct not to inject young children, but relying on alternative immunisation was dangerous.
"It is an absolute myth. Some people will believe they are doing the right thing using natural remedies, but it gives a false sense of security.
"There is no evidence that natural remedies give any immunity at all."
An "increasing tide of people" was starting to speak out about vaccine objectors whose argument was based on "myths and falsehoods", he said.
"We work to find common ground with all our patients, even those opposing immunisation, but it's hard to marry pseudoscience and emotion with something so overwhelmingly clear."
A Family Court judge this week ordered a couple to immunise their eight-year-old daughter according to government health guidelines, in a rebuke to the homeopathic regime pursued by the mother.
The mother lost a bid for an injunction against her ex-husband after he secretly took their daughter to a traditional doctor for injections.
The Australian Academy of Science has launched a booklet to give parents the facts about immunisation and counter anti-vaccination "misinformation".
Academy president Suzanne Cory said the number of vaccine objectors was rising, and that was a dangerous trend.
"There are now 30,000 children in Australia who are victims, if you like, of their parents who are vaccine objectors," Professor Cory said.