Stephen Curry (left) of the Golden State Warriors is defended by Danny Green of the Toronto Raptors during Game 5 of the 2019 NBA Finals at Scotiabank Arena on Monday in Toronto, Canada. Photo: VCG

The NBA will bar players from wearing "ninja-style" headbands next season amid safety concerns, ESPN reported on Monday.

Several players including All-Star Jimmy Butler sported the headgear last season, a band of fabric tied at the back of the head with the two ends flowing loose.

However, the on-court fashion trend had never been formally approved by the NBA, and now the league has moved to outlaw the accessory.

"The ninja-style headwear is not part of the NBA uniform and hasn't been through the league approval process," NBA spokesman Mike Bass told ESPN in a statement.

Philadelphia 76ers player Mike Scott was critical of the decision while other players were bemused by the ruling.

"I love that someone at the NBA had to type the words 'ninja-style (headwear)' and 'consistency of size and length' as their job today," wrote the Detroit Pistons' Blake Griffin.

AFP