The former world number one had been due to compete in the tournament that begins next week but her first year back in the sport after becoming a mother is now at an end - although she will be present at the event as a spectator.

Osaka said: "I’m really sorry that I have had to withdraw from competing at the Prudential Hong Kong Tennis Open and the rest of this tennis season.

"I love visiting the tournament and despite the obvious disappointment of not being able to play, I want to reassure all my wonderful Hong Kong fans that I will still be attending the event.

"I am very much looking forward to meeting you all.

"There is a wonderful line-up of world-class players coming to the tournament and I want to wish them all the best of luck in this exciting event."

Osaka has struggled for form since returning to the court after giving birth to daughter Shai last year and explained that the lack of progress in terms of her performance has been difficult to bear.

The four-time Grand Slam champion said: "My biggest issue currently isn't losses though, my biggest issue is that I don't feel like I'm in my body.

"It's a strange feeling, missing balls I shouldn't miss, hitting balls softer than I remember I used to. I try to tell myself, 'It's fine you're doing great. Just get through this one and keep pushing.' Mentally it's really draining through."