
The Frenchwoman who won Grand Slam titles in Melbourne and Wimbledon two years ago was joined by China's Li Na in withdrawing.
Mauresmo is suffering with a left adductor strain while Li has a knee injury. Mauresmo underwent appendix surgery last February and missed several months of play while recovering.
"It's very disappointing to me that I won't be able to compete in Sydney this year," Mauresmo said in a statement. "Unfortunately I have re-injured my left adductor.
"I felt it yesterday during my training session and did not practise today.
"This is an injury that I am familiar with and know that it will not get better overnight. I know that I would not be 100 per cent fit and ready to play on Monday.
"I have to take a few days to rest in order for it to get better."
Li, last player directly into the main draw and a 2007 semi-finalist, said: "The problem with my knee seemed to get a little worse after I tried to practise this morning and I just could not move very well."
Both face a rush to fitness with the Australian Open starting a week from Monday.