Popular sushi chain Sushiro on Wednesday expressed concern after a video showing a boy apparently putting a communal tong in his mouth at one of its restaurants was circulated online.

The video showed the boy playing with a tong – used to pick up slices of ginger – with his hand and mouth, before dropping the utensil.

"All ginger slice containers and ginger slice tongs in the store have been thoroughly cleaned and disinfected," Sushiro said in a statement in response to the incident.

"Sushiro Hong Kong severely condemns this behaviour and will seriously respond to this incident, including taking relevant legal actions."

The chain also said it will reconsider the way it provides cutlery and plates, adding it will strictly implement quality control measures.