LISTEN ABOVE: Larry Williams speaks to General Manager for Public Affairs at Retail NZ Greg Harford about the supermarkets joining forces to fight obesity.  

As of today, the country's major supermarket chains have all signed a Retail NZ pledge to work with the government in implementing its Childhood Obesity Plan.

Foodstuffs said it's re-focusing, and speeding up, its healthy food initiatives to help tackle childhood obesity.

Countdown's also adding a confectionary free check-out at every one of its stores, as part of its commitment to fighting obesity.

Countdown's James Walker said they're also re-formulating their private label products, and continuing their free fruit for kids programme, where they give out 50 thousand pieces of free fruit a week.

"Customers make their own choices. But we can do things that help inform and educate them about healthier choices."

Foodstuffs managing director Steve Anderson said they're continuing the food education programmes they started in 2007, and will complete their health star ratings programme by 2018.

"We've got fifteen hundred products in our private label - that's Pam, Budget and Value, and already we're at 40% of those products which have health star ratings.