Spanish champion Rafael Nadal isn't at home in Majorca fishing or playing golf for one reason - he believes he can still win the Australian Open.

The 14-time grand slam winner hasn't won a major since his ninth French Open title in 2014, and has largely struggled with injuries and form in grand slams since.

After missing Wimbledon with a wrist injury, his best result last year was a fourth-round appearance at the US Open where he was defeated by Frenchman Lucas Pouille.

Nadal turned 30 last June and his world ranking slipped to No.9 by year's end - but he's not ready to walk away from the game he loves just yet.

"If I don't believe that I can be competitive, and when I mean competitive is fighting for the things that I (fought for) during the last 10 years, I will be probably playing golf or fishing at home," Nadal said.

"I am being honest with this.

"If I am here is because I believe ... I can fight for the things that really motivate me."

Nadal will not carry any injuries into this Australian Open but the veteran responded with a wry smile when asked about his physical condition.

"Pain-free is a long time ago," he said.

Nadal will be aided by close friend Carlos Moya as he attempts to win his second Australian Open.

The former world No.1 joined Nadal's coaching staff in December after finishing a successful stint with Canadian star Milos Raonic.

"I know him very well ... I know he wants the best for me," Nadal said of Moya.

"He could be a good help for me and at the same time for the rest of the team.

"He's a person who loves this sport. He's a person who knows my tennis very well."

Nadal, seeded ninth, will meet German veteran Florian Mayer in the first round at Melbourne Park on Tuesday.