McDonald's said by June all its Happy Meals in the US would contain 600 calories or less - around 2500kj.
While there are no plans as yet to change the Happy Meal menus in New Zealand, McDonald's NZ spokesman Simon Kenny said the company would likely compare New Zealand's offering to the commitments made in the US and change the menu to suit.
New Zealand's Cheeseburger Happy Meal and 6-pack McNugget Happy Meal are already around 600cal, he said.
But there was still room for improvement in fat and sodium levels here, which would require reformulation of cheese, sauces and buns.
"People think a cheeseburger is a cheeseburger is a cheeseburger anywhere in the world but actually a lot can vary based on the local market."
The company said in a statement it had already been making its New Zealand menus healthier for 15 years.
"Customers tell us they still want to be able to choose classic McDonald's items for their children, but appreciate the added choices, and the work we are doing on nutrition and ingredients," it said.
"Some examples of what we have done in recent years include reformulating products to reduce levels of salt, saturated fat and sugar, and adding choices like apple slices, yogurt and grilled chicken."
Since 2007 the menu board picture has only shown a Happy Meal with a grilled chicken snack wrap, water and apple slices.