Jason Momoa has apologised to Chris Pratt after slamming him for using a plastic water bottle.

The Aquaman actor, who has launched a campaign to clamp down on the use of plastic, was horrified when his pal posted an Instagram shot of himself working out on Tuesday while holding the bottle, and had to fire back.

"bro i love u but wtf (what the f**k) on the water bottle?" Momoa asked. "no single use plastic. come on."

His remark hit headlines worldwide, prompting the actor to return to Instagram to apologise to the Guardians of the Galaxy star.

Sharing a snap of himself and his children posing with Pratt, Momoa wrote: "BRO you know my children and I are madly in love with you and I love everything you do. I'm sorry this was received so badly today I didn't mean for that to happen.

"I'm just very passionate about this single use plastic epidemic. the plastic water bottles have to stop i hope u make a reusable water bottle for amazon so we all can purchase. You're an inspiration to many I'm one of them. I'll send you a case of MANANALU. All my Aloha, Da Momoa's."

Momoa is doing his best to eliminate single-use plastic bottles by launching Mananalu Pure Water, which comes in 100 per cent recyclable aluminium cans.

Pratt has not yet responded to either of Momoa's messages.