Russian-born tennis world number 12 Daria Kasatkina announced Saturday she is switching to play under the Australian flag, reports AFP.

The 27-year-old, who has previously described the war in Ukraine as a "nightmare", said on Instagram she was "delighted" to reveal Australia had approved her application for permanent residency.

Kasatkina said she loved Australia and looked forward to making Melbourne her home.

"As part of this, I am proud to announce that I will be representing my new homeland, Australia, in my professional tennis career from this point onwards," she said.

"Obviously there are parts of this decision that have not been easy," the player added, thanking her family and coaches for their support.

"I will always have respect and fond appreciation for my roots, but I am thrilled to start this new chapter in my career and my life under the Australian flag."

Kasatkina has previously called the war in Ukraine a "nightmare" and criticised Russia`s attitude towards homosexuality after revealing she was gay.

Tennis Australia hailed her switch with a message on social media: "A warm welcome to the Aussie tennis family, Dasha," along with a heart emoji.