Both defending champion Petra Kvitova and second seed Agnieszka Radwanska have withdrawn from the Sydney International build up event ahead of the Australian Open which starts next week.
Czech Kvitova pulled out due to a reported gastrointestinal illness which means she won’t be defending her title that she won last year.
Polish world number four Radwanska has pulled out due to a left-leg injury.
In an interview, Kvitova said she was disappointed to not be participating in Sydney.
"I'm really disappointed to have to withdraw from the Sydney International but unfortunately, I am still not feeling well," Kvitova said.
Radwanska, who won the Shenzhen Open title on Saturday, told media that she was forced to pull out of the Sydney event as she needed to rest her leg.
"I'm really sorry that I can't play in Sydney this week," she said.
"I am feeling very confident in my game at the moment and the results are there, but after five matches in the past week, my leg needs some recovery time."
The Australian Open starts in Melbourne on January 18.