Seven-times Grand Slam winner Venus Williams [ Images ] has withdrawn from this month's Australian Open [ Images ] saying she is not ready to return to action after being sidelined because of health reasons.

The American has not played competitively since withdrawing from the US Open [ Images ] in September ahead of a second round match and has been receiving treatment for Sjogren's syndrome, an auto-immune disease that causes fatigue and joint soreness.

The five-times Wimbledon [ Images ] champion said she is targeting a return to action in February.

"I regret to announce that I am withdrawing from the 2012 Australian Open. After several months of training and treatment, I am making steady progress to top competitive form," Williams, 31, said in a statement on her website.

"My diet and fitness regimen have allowed me to make great strides in terms of my health and I am very close to being ready to return to WTA competition."

The Australian Open starts on January 16.