Rafael Nadal on Wednesday insisted he will be "competitive" when he returns to professional tennis next month after enduring nearly a year out of action due to injury.

The 22-time Grand Slam champion has undergone surgery twice in 2023 after struggling with a hip injury.

He has said next year will likely be his last season before retirement and announced last week he would make his comeback at the Australian Open warm-up event in Brisbane, which runs from January 1-7.

"I don't know at what level (he will play at), I don't know what to expect, I have no idea, but I don't care right now," Nadal said in a video posted on social media.

"I'm just happy to be back and with great excitement to make the effort that is necessary to have fun and I believe that I will be competitive."

Nadal last played at the Australian Open in January, losing in the second round to American MacKenzie McDonald.

He originally hoped to be back in time for the clay-court season and Roland Garros, where he is a 14-time French Open winner, but had to end his campaign early.

The 37-year-old Spaniard has slipped to 664th in the world rankings while sidelined.

"It's been a long year in which I've gone through many phases, from trying to get back to compete at the clay season, week after week, disappointment after disappointment," said the former world number one.

"Of course I have had many doubts, of course there were moments where it seemed impossible that this moment would come, but we've maintained the work, spirit and hope and I think I am ready."

Nadal is a two-time Australian Open champion, in 2009 and 2022.

He has slipped behind old rival Novak Djokovic in the all-time list of Grand Slam singles titles, as the Serb won three this year in his absence to take his tally to a record 24.

"I have finally had good training weeks at a level that allows me to have the possibility to compete again," added Nadal.

"I have gone through many phases, but today I think it's time -- I'm coming back in a tournament that I've played in the past, that I'm familiar with...

"I know it's a difficult tournament but I hope to be ready to compete, I don't aspire to anything else but to be competitive."