The 2517 postcode - Woonona, Woonona East and Russell Vale - has the second highest childhood immunisation rates in the country, according to a new report.
The National Health Performance Authority (NHPA) report revealed 98.4 per cent of five-year-olds within this postcode were fully immunised in 2012-13, second only to suburbs in the Goulburn Valley in Victoria, which had 99 per cent coverage.
There were slight variations in suburbs across the Illawarra Shoalhaven Medicare Local catchment area, which as a whole fared well with 93.8 per cent of children fully immunised by the age of five, compared with the national average of 91.5 per cent.
However, the report also revealed just over 75,000 children aged one, two and five years were not fully immunised in 2012-13, with almost 15,000 registered under "conscientious objector" provisions. That included 185 conscientious objectors in the Illawarra Shoalhaven.
Milton GP Dr Brett Thomson said childhood immunisation significantly decreased the possibility for infection and spread of diseases in the community, such as whooping cough and measles.
"We have vaccine-preventable diseases - these vaccines are a wonderful benefit to society that the government, the medical profession and health agencies all support," he said.
"You don't see cases of tetanus any more, diphtheria hasn't been around since the 1950s - you don't see these diseases because we immunise against them.
"Even in my short lifetime, diseases like haemophilus, which can cause meningitis and epiglottitis, have become pretty trivial due to vaccines."
Dr Thomson said none of the anti-vaccination literature stood up to scrutiny - "it's unsubstantiated, untrue and unscientific".
"We have the advantage of herd immunisation where lots of people are immunised so there's a tendency for the disease not to propagate," he said. "So those who are not immunised are getting the benefit of the herd as the disease doesn't have enough susceptible people for it to spread."
The NHPA report also showed variations in the uptake of the cervical cancer vaccine nationally, which is provided free in schools for children aged 12 and 13.
Sixty-five per cent of girls turning 15 in 2012 in the Illawarra and Shoalhaven were fully immunised, just under the national average of 70 per cent.
NHPA chief executive Dr Diane Watson said the report, released this week, showed health professionals which areas now needed to be targeted - including some affluent Sydney suburbs such as Neutral Bay, Paddington and Manly where immunisation rates were low.
"Through local-level reporting, we can clearly identify areas in Australia with low rates of childhood immunisation. This information can be camouflaged by national, state and territory level reporting," Dr Watson said.