WELL-OFF eastern suburbs and northern beaches parents helped drive a recent epidemic of whooping cough because many refused to vaccinate their children.

And health authorities warn that NSW could be facing another outbreak as more cases than usual have been seen recently in the areas where the epidemic started.

The highest rates of so-called "conscientious objectors" to immunisation are in parts of the north coast - such as Byron Bay - where 12 per cent of children born between 2001 and 2007 were never immunised for any condition.

But in Sydney up to 8 per cent of children were unvaccinated in wealthy beach and harbourside suburbs such as Bondi, Coogee, Vaucluse and Manly, the second national audit of immunisation coverage in Australia reveals.

The deputy director of surveillance at the National Centre for Immunisation Research and Surveillance, Rob Menzies, said these low rates could be dangerous. "It poses a risk for some diseases [and] the one we are having the most trouble with at the moment is whooping cough," he said.