Former women's world number one Naomi Osaka has withdrawn from the Australian Open.

Tournament organisers confirmed Osaka's withdrawal on Twitter on Sunday afternoon, but they did reveal the reason behind her decision.

Osaka is a two-time winner at Melbourne Park, having claimed the women's singles title in 2019 and 2021.

Her withdrawal comes a day after men's world number one Carlos Alcaraz and seven-time major singles winner Venus Williams pulled out of the Australian Open.

Osaka was at long odds to play in Melbourne after posting photos on social media of herself holidaying in Europe last week.

The 25-year-old's decision not to play the Australian Open will only further heighten concerns the four-time major singles champion may not return to the tennis court at all.

She took a mental health break after sitting out the 2021 French Open and later revealed she had been struggling with depression and anxiety for several years.

Osaka has not played since withdrawing from the second round of the Pan Pacific Open in Tokyo last September with abdominal pains and has won only one completed match since last May.

She crashed out in the first round of her previous three events, including the US Open, which she has also won twice.

Osaka's last victory was an abbreviated one to say the least, coming after just one game against Daria Saville when the Australian suffered a torn ACL in Tokyo.

Her scratching is another blow to Australian Open organisers already reeling from the retirements last year of Ash Barty, Serena Williams and Roger Federer.

Former Australian Open finalist Simona Halep is also not competing at Melbourne Park.

The withdrawal of Osaka, ranked 42 in the world, means Ukrainian Dayana Yastremska gains entry to the women's main draw.

AAP/ABC