An incentive to offer 'cash rebates' to schools that place lunch orders with McDonald's has been slammed by a parenting group who claim it's sending unhealthy messages to children.

McDonald's sent letters to schools at Mildura in rural Victoria this month saying the fast food chain could deliver burgers, fries, nuggets and desserts to students.

The letter, which was forwarded on to The Parents' Jury and the Obesity Policy Coalition by a parent, promises to give free drinks and a nine percent cash rebate if the whole school participates.

McDonald's sent letters to schools at Mildura in rural Victoria this month saying the fast food chain could deliver burgers, fries, nuggets and desserts to students

The local McDonald's store suggested schools could use the lunch orders as a fundraiser, end of term treat or delivered to school functions.

The letter includes an order form and notes that offers of food are also available for students receiving encouragement or achievement awards.

Parents' Jury spokeswoman Dimity Gannon said she was horrified by the promotion.

'Allowing McDonald's to be promoted in schools normalizes the consumption of fast food, undermining both parents' and schools' efforts to teach children about nutrition and instil healthy eating habits,' she said.

Ms Gannon, whose group represent 7,000 parents in Australia, said the promotion undermined healthy eating messages that schools were trying to get across.

The letter, which included an order form for food, promised to give free drinks and a nine percent cash rebate if the whole school participates

Parents' Jury spokeswoman Dimity Gannon said she was horrified by the promotion as it undermined the healthy eating message schools were trying to get across

Obesity Police Coalition executive manager Jane Martin argued the attempts by McDonald's to promote 'unhealthy food' to children was insidious.

'This deliberate targeting of children in these settings shows that McDonald's is putting profit ahead of children's health. This is from a company that claims to be committed to responsible advertising to children,' she said.

McDonald's told The Age the chain's restaurants were sometimes approached by schools to provide assistance for fundraisers.

'Provided the school has parental permission, we do not see an issue with them hosting a McDonald's lunch as a fundraiser or end of term treat,' a spokesman said.

'McDonald's does not engage in any communications in Australian schools unless requested by, or agreed with, the school administration.'