Olympic gold medalist and America's Cup sailor Peter Burling has taken a swipe at My Food Bag after finding the company's beach balls floating in the Waitemata Harbour.

On Tuesday Burling took to Instagram, posting an image of a deflated My Food Bag beach ball, saying his finding was "sad" and "not cool".

"Hey [My Food Bag] how about heading out to Rangitoto and picking up the 30 odd more beach balls that floated out to sea today?! Not cool," Burling wrote.

"Sad seeing all these floating out into the Gulf today."

On Tuesday My Food Bag delivered beach balls to Mission Bay as part of their Russell the Brussels Sprout NZ summer giveaway to its customers.

"We're popping in a FREE Russell Beach Ball in all My Food Bag and Bargain Box deliveries this weekend, so make sure you order by midnight to snatch yours up," the company posted on social media last week.

My Food Bag CEO Kevin Bowler said he was disappointed to hear the beach balls weren't cleaned up and made their way out to sea.

"So disappointed to learn that some people left more than their footprints on the beach with several of our Russells making their way out into the harbour, especially when we handed out tips on how to upcycle and recycle the ball," he told Stuff.

The company received backlash following their social media post, with some saying the beach ball promotion "seems out of line" with what the "company's values were around sustainability".