Twice former champion Jennifer Capriati [ Images ] has withdrawn from next week's Australian Open [ Images ] because of injury, tournament organisers say.

Tennis Australia [ Images ] announced on Tuesday that the world number six had pulled out because of a back problem.

Capriati won the Australian Open in 2001 and 2002 and would have been among the favourites in Melbourne [ Images ] this year.

The American is the latest in a series of top players to withdraw from the first Grand Slam of the year.

Serena Williams [ Images ] announced last week that she would not be defending her title. Four-times winner Monica Seles [ Images ] and 1995 champion Mary Pierce [ Images ] have also pulled out.

There are also concerns about world number two Kim Clijsters [ Images ] after she injured her ankle in the Hopman Cup last week while Jelena Dokic [ Images ] is unlikely to play after pulling out of two warm-up events citing "personal reasons".