A swath of inner-city, affluent Melbourne suburbs are falling below safe vaccination rates for children, leaving doctors worried about an increased risk of potentially fatal diseases.

Victoria has one of the highest immunisation rates in the country, but Health Department data shows several inner-city and bayside areas, including St Kilda, Fitzroy North, Camberwell, Toorak and Brighton, are below the state average.

Just over 93 per cent of Victorians have received the MMR (mumps, measles and rubella) vaccine, but pockets of Melbourne are now dipping below this rate, a trend Australian Medical Association Victoria vice-president Dr Tony Bartone says can be problematic.

''We have a cast-iron dogma: anything under 93 is unsafe,'' he says.

Health Department data shows just 81.29 per cent of five-year-olds in the City of Melbourne are immunised. The City of Stonnington, which includes Toorak and South Yarra, is at 86.51 per cent, City of Port Phillip (Albert Park, St Kilda and Elwood) 88.13 per cent, City of Bayside (Brighton, Hampton and Beaumaris) 90.36 per cent, City of Yarra (Fitzroy North and Richmond) 90.56 per cent and City of Boroondara (Kew, Camberwell and Hawthorn) 92.31 per cent.

The MMR vaccine is given to children at 12 months and 18 months. To be considered immunised a child must have received both doses and catch-up doses are available on request.

Dr Bartone worries that educated professional parents from ''affluent'' suburbs are either underestimating the risk of preventable diseases or not immunising over ''unsubstantiated claims linked to autism". He said research had proved ''beyond doubt'' that was not the case.

New father Dave Hawkes, 37, a Melbourne University virologist from Footscray, said he and his wife Amanda consulted a doctor about the potential risks of immunisation when their first child, Tom, was born in November.

''I think there are risks and benefits, but the benefits far outweigh the risks,'' Dr Hawkes said. "The information that is omitted is what is misleading for parents. If you're reading something about vaccination and it doesn't give you a risk and benefit, it is probably biased."

In Victoria, parents are required to provide their child's vaccination history to primary schools, but there are no requirements for children who have not received the MMR vaccine.

Mother of eight, 42-year-old Tasha David, of Melton West, is a member of the anti-immunisation lobby that was known as the Australian Vaccination Network until it was ordered by a court to change its name last year.

She says she made the conscious decision not to immunise her two youngest children when her first six developed chronic illnesses after receiving all the recommended vaccinations. Three have autism ranging from mild to severe, she says, while her youngest children have no serious health issues.