More than half of Australia's parents are worried about the safety of childhood vaccines, a survey has revealed, prompting concerns that a shift in support for vaccination could lead to reduced coverage rates and outbreaks of disease.

More than 1300 Australians, including 400 parents, gave their views in Australia's first national survey of attitudes to vaccination, commissioned to coincide with the release of a new television documentary on vaccines.

The survey, conducted by Australia Online Research, found that 53 per cent of parents had general concerns about vaccinating their children. Of those concerned parents, 45 per cent chose to vaccinate anyway, while 8 per cent withheld or delayed vaccines.

One in four parents were worried about a specific aspect of vaccination, with an increasing number of vaccines, ''inadequate safety testing'' and fears a child's immune system could be overloaded among the most common.