Garbine Muguruza admitted she was not yet at peak fitness ahead of the Australian Open after a tough start to the year.

Muguruza retired at the Brisbane International due to cramps and then withdrew in Sydney because of a thigh injury.

The 24-year-old two-time grand slam champion said she was hoping to be at her healthiest when the year's first major begins on Monday.

"I wish to be more," Muguruza said on Saturday when asked if she was at 100 per cent.

"Well, you always want to be perfect before a grand slam, but you're never perfect. But I feel I'm much better every day."

Muguruza has played just one full match – a win over Kiki Bertens in Sydney – ahead of the Australian Open.

The Spanish world number three, who faces France's Jessika Ponchet in the first round in Melbourne, said it was far from ideal preparation, but she is remaining upbeat.

"It's true, I would like to have played more matches. But you never really know how it's going to start the year," Muguruza said.

"I only played two matches, but I felt that my tennis was good. Maybe my fitness was a little bit, you know, there. I don't know.

"I think sometimes you don't need that many matches.

"With my experience, sometimes you play very good, and you don't need 25 tournaments before, sometimes you need it, so... so far, I am OK."