Surfing champion Mick Fanning's brother Peter dies, aged 43

• Bede Durbridge suffers fractured pelvis in Pipeline wipeout

The brother of Australian surfing champion Mick Fanning has died, just hours before Fanning paddled out to compete for the world championship title at Pipeline in Hawaii.

Peter Fanning, 43, died in his sleep, according to Surfer Magazine, although no further details were available about the circumstances of his death.

Emotional: Mick Fanning said he was dealing with some "personal" issues after competing. Photo: Screengrab

Fanning is believed to have been told of his brother's death before entering the water for the third round of the Pipe Masters in Hawaii.

Despite the tragic news, Fanning went on to win his third and fourth round showdowns in the event, on Hawaii's North Shore.

In an emotional interview after his heat four win against Kelly Slater and John John Florence, Fanning broke down as he said he was dealing with some "personal" issues, although he did not say what they were. 

"It's been a huge day. Just got some personal stuff going on at home, and just yeah, it's sort of heavy to talk about right now," he said, his voice wavering.

Fanning then hugged the World Surf League commentator who was interviewing him, before leaving the podium.

Before his heat, he had spent several minutes on the beach in quiet reflection, before picking up his surfboard and looking skyward for several seconds.

Rip Curl, which sponsors Fanning, confirmed that Peter had passed away.

"This is a sad and unfortunate incident and is a private matter for the family to deal with," a Rip Curl spokesperson told the ABC.

"We ask that the media respect their privacy. But we can confirm Mick's older brother Peter has sadly passed away. We will not be commenting further."

The Seven Network said a close family friend of Fanning's confirmed that Peter was staying at Fanning's Gold Coast home following his recent divorce. Peter is believed to have three children.

The World Surf League, which is the governing body for professional surfers, said it was aware of the reports of Peter's death.

"The WSL are aware of the reports but have not heard from the Fanning camp regarding them so we're in no position to comment," it said in a statement.

Fanning lost one brother, Sean, in a car crash in 1998.

Fairfax Media has contacted Fanning's manager and family for comment.

Fanning held surfing's No.1 ranking as he headed into the Pipe Masters, which will decide whether the Australian star wins a fourth world title.

Fanning won his round-three heat against Pipeline specialist Jamie O'Brien. In an interview after that heat, earlier in the day, he made no mention of the reported tragedy.

"Jamie is probably the best guy out here, he surfs it the most, so I knew it was always going to be tough," Fanning said.

"I just got lucky at the start ... and kept trying to improve that score and go from there."

It has been a turbulent year for Fanning, who in July was knocked off his surfboard by a shark while competing in the final of South Africa's J-Bay Open in a terrifying encounter that was broadcast on live television.

When Fairfax Media spoke to Fanning's mother, Elizabeth Osborne, at the time of that incident, she said she thought she was watching her son die.

"I was too overwhelmed to even think about what was going on for Mick, I just saw my boy going down and, you know, that was absolutely terrifying because I have lost a son before," she said, referring to the death of Mick's brother Sean.

Mick has previously said that he believes Sean was the "angel on my shoulder" during his career, in which he has claimed three world surfing titles.

Last week, Fanning was among a group of surfers who helped bring young American Evan Geiselman out of the water at the famed Pipeline break.

Geiselman suffered a bad wipeout and nearly drowned, but is expected to make a full recovery