Novak Djokovic said he wasn't planning to replace Boris Becker in his coaching team and deflected criticism from the German about his work-rate as he prepared to defend his Australian Open title on Saturday.

Djokovic, seeking a record seventh Australian Open crown after being ousted as World No. 1 by Andy Murray, heads into the year's first Grand Slam with long-time coach Marian Vajda and his newly appointed assistant Dusan Vemic.

"I'm not thinking of bringing anybody in. This is the coaching team that there is," said Djokovic, who split with Becker after three trophy-filled seasons late last year.

Djokovic sidestepped a question about Becker's remarks that the Serb's training intensity had dropped during a sudden plunge in form in the second half of 2016.

"We've had amazing success. It's all I can say. I don't want to go back and comment on anything. I kept a very friendly relationship with Boris. We just went separate ways," Djokovic said.

In Melbourne, Djokovic, seeded two, will be hoping to show he's back to his best after a period of sustained dominance abruptly ended last year after the French Open.

The Serb bettered Murray in a thrilling final this month in Doha, a performance that suggested he may be regaining his edge -- although he insisted he was never "invincible".

"Nobody is invincible. I never thought of myself as a superior player on the court, even though of course at times I was very confident, I was winning a lot of matches," he said.

"But (I know) how it feels on the court if you get overconfident, that's why I don't want to get into that kind of state of mind.

"I still want to put myself in a position where I'm quite even to other players, fight for this trophy as anybody else, even though I'm defending champion."

Djokovic said getting back to World No. 1 wasn't his top priority. He starts the season with 12 Grand Slam titles, two shy of Rafael Nadal's tally and five off Roger Federer's 17.

"As a consequence of the results, if I become number one, that's great. Of course, that's what I want. But it's not my main priority, let's say," he said.

He faces a difficult first opponent in the shape of Fernando Verdasco, the Spanish left-hander with a "complete" game who ousted Nadal in five sets in last year's opening round.

"I still haven't had any nightmares, so I can't call it a nightmare draw. I just see it as a huge challenge. I hope I'll be able to deliver," Djokovic said.

Another challenge could be Australia's summer-time weather, with temperatures forecast to soar towards 40 Celsius (104 Fahrenheit) during the first week.

Djokovic has bitter memories of the Melbourne heat, after he was forced to retire with "heat illness" during his 2009 quarter-final against Andy Roddick.

"I don't know still a player that enjoys playing in 40 plus or 35 plus (degrees). It's same for everybody. It's not easy," he said.

"At the end of the day, that's what you expect. You come to Australia during the summertime, and the conditions can get quite challenging and extreme."