It is well known that fewer people are vaccinated in poorer neighbourhoods but Dr Hambleton said that ''perversely'' the data revealed there had been a reduction in vaccination rates in wealthier suburbs. ''These are parents who have got information, good information available and yet they are not vaccinating their children,'' Dr Hambleton said. There is also a worrying undercurrent of vaccine objectors who believe conspiracy websites and reject public health guidelines. These vaccine objectors ''should be ashamed of themselves'' for spreading misinformation and should be sanctioned, Dr Hambleton said. ''We need to look at the groups providing those anti-vaccination messages and we need to make sure we stop them . . . They are putting the community in danger.''

Some of Sydney's wealthiest areas have such low immunisation rates experts fear children could be at risk from deadly but preventable diseases, according the report, Healthy Communities: Immunisation rates for children in 2011-12, released on Thursday by the National Health Performance Authority. The prestigious northern and eastern suburbs, Manly and inner Sydney are four of the nine NSW local areas listed by the National Health Performance Authority as being ''at risk'' of outbreaks because of low vaccination rates. Dr Hambleton is also concerned about ''pockets'' in inner city Melbourne, Brisbane and Sydney and said it was ''no coincidence'' that there had been outbreaks of measles in northern NSW and south-east Queensland. Health Minister Tanya Plibersek, whose Sydney electorate covers some of the wealthier, more educated suburbs with worryingly low vaccination rates, disagreed with the suggestion that unvaccinated children be kept home from school. "I think that's a very difficult position to take because parents are making these decisions and children are suffering," Ms Plibersek said.

"If you don't vaccinate your child you're endangering their health. We don't want children's education to also be endangered". But parents should tell schools and child care centres if they have not immunised their children so they can be sent home from school if there are disease outbreaks, she said. Ms Plibersek said anti-vaccination campaigners, whose messages she described as "mischievous", persuaded only a small number of people. "It's less than two per cent of children that are not immunised because their parents are deliberate vaccine refusers," she said. "Remember that the larger group of parents not immunising are not doing it in a deliberate fashion because they have a medical or ethical or religious objection.

"They are doing it for a variety of 'life got in the way' reasons.'' As a mother, Ms Plibersek believes immunising children is "one of the best and most effective ways of keeping them healthy" and important to protect the community. She said the government had taken several measures to increase vaccination rates. These include linking parents' eligibility for some family payments to the immunisation status of their children. But experts say wealthy families are unswayed by government tax benefits linked to immunisation, and often forgo finishing their children's vaccine schedule because of things such as overseas holidays. Authority chief executive Diane Watson said there were about 77,000 children who were not fully immunised, and 32 local communities at risk of outbreak.

''These are remote areas, regional areas and urban areas . . . they are in high-income communities, low-income communities,'' she said. ''We do know these children are at increased risk of catching diseases such as measles and whooping cough.'' Rates in many indigenous communities were particularly worrying. In NSW, immunisation rates were at risky levels for children at age one, two and five in the coastal areas of the Richmond Valley, including Byron Bay and Lennox Heads. Other at-risk areas, with immunisation rates at 85 per cent or below, most commonly among five-year-olds, include the Sydney inner city – stretching from Darling Harbour to St Peters and Rosebery – the Richmond Valley hinterland, the south coast, the Blue Mountains and Kempsey-Nambucca. A deputy director of the National Centre for Immunisation Research and Surveillance, Rob Menzies, said in some wealthy suburbs parents believed websites over health authorities. ''There's been slight increases in the population of people who are somewhat sceptical or not completely supportive of immunisation,'' he said. ''I think that's a misplaced scepticism.''

NSW Health's head of health protection, Dr Jeremy McAnulty, said levels of vaccine-refusal were particularly worrying on the north coast. ''But in other places, for example eastern Sydney, there's much more affluence and [overseas] travel, so from what we understand . . . a fair proportion have travelled overseas and started vaccination but not finished it,'' he said. An associate professor in the school of public health at the University of Sydney, Julie Leask, said parents should not assume that unvaccinated children were safe. Loading ''I think this is a warning to the community that we can't rely on having herd immunity . . . so it's even more important that these kids are up to date and parents who have hesitance about immunisation reconsider their decision,'' she said.