Emma Raducanu has withdrawn from this week's WTA event in Auckland, saying a back injury she has been nursing in recent weeks had not improved as much as she hoped.

Raducanu was seeded sixth for the tournament and was due to play her opening match of the new season on Tuesday against American Robin Montgomery.

The 22-year-old will now fly to Melbourne to continue her preparations for the Australian Open, which starts on January 12.

Second-seeded Elise Mertens also withdrew on Tuesday from the tournament, citing an ankle injury, with Jodie Burrage taking the Belgian's place in the competition.

"Tried my best to be ready," Raducanu said. "I love Auckland and the fans here, but unfortunately I picked up a back niggle and won't be ready in time."

The tournament was set to be Raducanu's first since hiring renowned fitness trainer Yutaka Nakamura, who had previously worked with Maria Sharapova and Naomi Osaka.

Raducanu has been beset with fitness issues since her stunning triumph at the US Open in 2021, spraining ligaments in her foot in Seoul in September and could only play three further matches last season.

She won them all, on national duty for Great Britain at the Billie Jean King Cup Finals, but will now head into the first grand slam of the season with no match practice.

Despite an impressive year, seeing her climb to 56th in the WTA rankings, she will not be seeded for the Australian Open.