Vera Zvonareva of Russia and Flavia Pennetta of Italy pulled out of the Pan Pacific Open tennis tournament that gets under way this weekend, organisers said on Wednesday.

Zvonareva, who captured her second Grand Slam doubles title at the Australian Open in January, is suffering from a viral disease, while Pennetta has a right wrist injury, the organisers said.

Aleksandra Wozniak of Canada and Vania King of the United States moved up to the main draw, they said.

The tournament will be led by world number one Victoria Azarenka of Belarus and former world number one Maria Sharapova of Russia.