Australia's Dairy Farmers and the Federation of Canteens in Schools have developed a smart card that allows parents to influence their offspring's food choices in school cafeterias.

When swiped by canteen staff, the prepaid card brings up a photo-ID of the child and a list of foods they are banned from buying, as well as any spending limits.

Dairy Farmers group marketing manager Andrew Lawrence said the card was about improving children's' health and giving parents peace of mind. He said it gave parents the opportunity to prevent their children buying foods high in fat or sugar, foods a child may be allergic to, or foods they should not have for health reasons, such as diabetes.

Data is tracked, and children can be rewarded for making healthy food choices.

With childhood obesity on the rise, any tool that helps combat it is worthy of closer investigation. Some groups, however, feel it is more important to educate children so they make good food choices off their own bat. There is also of course the likelihood that children banned from buying fries will find a way to get their friends to buy them on their behalf.

The software for the programme costs A$121 (US$66.4) per month to rent, reports AAP.