Fruit, vegetables and freshly made food will make up at least 75% of NSW school lunch menus as part of a new overhaul aimed at reducing childhood obesity.

Remaining menu offerings will need to have a Health Star Rating of 3.5 stars or higher under the Healthy School Canteens Strategy, announced today.

Ms Berejiklian said the overhaul would go some way in helping her achieve her "Premiers Priority" of reducing childhood obesity by five percent by 2025.

"Obesity has significant health impacts for children with around one in five NSW children between the ages of 5 and 16 being overweight or obese," she said in a statement.