CANBERRA - Aussie parents might be savvy enough to know what their kids are watching on television and how they use the internet.

But when it comes to food, they place their trust in sporting heroes.

If a big name says junk is good, many will buy it.

And if the packaging says it's healthy - even if it is not - so much the better, regardless of what the compulsory nutritional information in discreet panels elsewhere may say.

The new insights on shopping for kids' food came in a Cancer Council Victoria study published in the journal Public Health Nutrition, supported by the Obesity Policy Coalition.

The coalition includes the council, Diabetics Australia, the Victorian Health Promotion Foundation and the World Health Organisation Collaborating Centre for Obesity Prevention at Deakin University.

The study asked parents to choose between an unhealthy food product and a healthier alternative, based on the packaging.

Although they were pointed to the nutritional information panel, which includes data on energy, protein and fat content, only 44 per cent bothered to read it.

Presented with a choice of two products, those who ignored the panel were two and a half times more likely to select the unhealthy option if it was endorsed by a sporting celebrity, the study said.

They were also almost twice as likely to make the same choice if the packaging proclaimed a nutritional advantage, such as being a source of fibre.

The study's lead author, Dr Helen Dixon, of Cancer Council Victoria's Centre for Behavioural Research in Cancer, said parents were influenced by their perceptions of how healthy a product was when buying food for their children.

"We've shown that this is affected by promotions highlighting positive elements of food and recommendations by athletes."

The Obesity Coalition's senior policy adviser, Jane Martin, said it was unrealistic to expect parents to always read and compare the data on nutritional information panels.

"If Australia is serious about combating our childhood obesity epidemic, there needs to be greater regulation of nutrient claims made by food manufacturers.

The coalition supported "traffic light" labelling, a simplified system of displaying fat, saturated fat, sugar and sodium levels in three separate coloured circles.

Foods low in these are rated green, medium amber, and high red.

The system was recommended in the federal food labelling review released last month.

The coalition also backed the review's call for a ban on misleading endorsements by sports stars.

"They were things like a high-sugar breakfast cereal, a snack pack with cheese biscuits, icecream, chicken nuggets, that kind of thing. When a sporting person was on it, people felt the product was healthier, it was higher quality and they are more likely to buy it.

"We've just had a summer of cricket where KFC has been incredibly heavily promoted, so there is no doubt that these associations with sport do convey attributes of health and people are swayed by them."

Meanwhile, another federally funded study has found that Australian parents fare better in keeping tabs on their children's television and computer habits.

The latest annual Growing up in Australia: the Longitudinal Study of Australian Children found 96 per cent of parents surveyed were aware of how their children used media and technology, and imposed rules about the TV programmes they could watch.

More than 90 per cent of parents also imposed rules on computer use.

The study found only about one in five worried about their children's use of technology.

The study follows 10,000 children over the course of their youth, and measures their physical, learning and cognitive development as well as social and emotional functioning.

The latest report includes findings from almost 6000 of the parents involved.

It found 96 per cent of 9 and 10-year-olds had access to a computer at home and used it at least once a week for homework, playing DVDs, finding information not related to school, playing non-internet games, and visiting social networking sites.

One in 10 also own their own mobile phone.

- Additional reporting AAP