By Ian Ransom

MELBOURNE (Reuters) - Rafa Nadal's preparations for next week's Australian Open continue to be hampered by flu and the illness could still take "a few days" to shake, the world number one said on Friday.

"(The virus is) improving every day. Hopefully, that's gonna be completely recovered for next Monday... (but) it's still a little bit (there)," a gravelly-voiced Nadal told reporters, shortly after getting rained on during a sponsorship photo opportunity.

"But I don't have fever and I need a few more days, maybe, but hopefully it's going to be fine."

The 24-year-old Nadal will bid to become the first man to hold all four grand slams concurrently since Rod Laver in 1969 but delayed his trip to Australia after coming down with the illness and has been confined to indoor training sessions at Melbourne Park due to rainy weather throughout the week.

Nadal's concerns for his illness had not extended to his choice of wardrobe and the Spaniard emerged from a sponsor's car into pouring rain wearing a T-shirt and jeans.

The Spaniard flashed his broad grin for the cameras between umbrella-toting officials before lamenting that the unseasonable Melbourne weather was hardly helping his recovery.

"No, the weather doesn't help a lot these days, unbelievable, it's the first time in my life with this weather in Melbourne," he said.

"Just nothing to do (about it), wait, practice in the inner courts ... We will see. The important thing is be prepared next Monday or next Tuesday.

"I remember a lot of times I didn't start playing the tournament at my best and I finished playing very, very good.

"Sometimes you start very well and finally you don't play that well.

"It's very difficult to say if I'm ready or not ready. The only thing I can say is that I did good work at the end of the season. I did all I could do to be ready here."

Nadal's preparations as defending champion last year were also under a cloud with the Spaniard out of form and still recovering from knee tendinitis.

The extent of the injury was not revealed completely until he retired hurt while trailing Briton Andy Murray 6-3 7-6 3-0 in their quarter-final.

Nadal bounced back spectacularly to win the year's three remaining majors and said painful memories of his last campaign had no bearing on his motivation at Melbourne Park this year.

"My motivation is the Australian Open, that's my motivation," the nine-times grand slam champion said, who has drawn Brazilian world number 96 Marcos Daniel in the first round of a tricky draw.

He faces a possible third-round hurdle against 31st-seeded countryman Feliciano Lopez or big-serving 20th seed American John Isner, before a potential fourth round encounter with 15th seed Marin Cilic of Croatia, a semi-finalist last year.

"Nothing bigger than this -- not because last year I had an injury, not because I have the chance to win the fourth grand slam in a row.

"For me the pressure is the same every tournament. The pressure is my pressure. I want to play well, to do the right things and we will see."

The Jan 17-30 Australian Open starts Monday.

(Editing by Ossian Shine)