Olympic gold-medal-winning Australian cyclist Stephen Wooldridge has died aged 39.

The Sydney-born athlete won gold at the 2004 Games in Athens as part of Australia's 4,000-metres track pursuit team.

He also won four world titles in the same event and took silver at the 2006 Commonwealth Games in Melbourne.

Cycling NSW said Wooldridge "was an inspirational figure in track cycling".

"Stephen was inducted into the NSW Sports Hall of Fame in 2015; an honour he was delighted to receive both personally and for the sport of cycling," Cycling NSW posted on Facebook.

Cycling NSW chief executive Phil Ayres said Wooldridge's death had devastated the cyclists who had trained with and rode with him.

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"Look, everybody's really shocked and I've just been speaking with one of Stephen's former colleagues on the bike, Brad McGee," Ayres said.

"All of that group they're still in contact from those days riding together riding around the world in the championships and they're all deeply saddened."

Friend and mentor Phill Bates said Wooldridge was survived by a son, a daughter and other friends and family.

"His infectious smile, gentleman attitude on and off the bike made him a very special person," he wrote on Ride Media.

"We are better for knowing him and worse off for losing him."

Bates said Wooldridge was not just a great cyclist, but a great man.

"He lit up the room. He would talk to anyone and everyone," Bates said.

"He was never trying to position himself as being a out and out champion, he was just like one of the guys and I think that's why everyone loved him so much."

Wooldridge struggled with mental health

Bates said Wooldridge had battled at times with his mental health, but the news left everyone "just gut-wrenched".

"Really can't believe it, it's something that most of us didn't see it coming," he said.

"Stephen is so well loved and liked by so many. He's got no idea how much effect he's had on people."

Wooldridge won his third of four world championship gold medals in Melbourne in 2004. ( Reuters: David Gray )

Former Olympian Gearoid Towey, the founder of Crossing the Line, which supports athletes transitioning from professional sport, said Wooldridge's death was "devastating for the sporting community".

"It's one that happens not regularly, but it happens from time to time," he said.

"It just shows you that the athlete community are just as vulnerable to mental health problems as the general population."

The death of Wooldridge came just months after former Wallaby Dan Vickerman took his own life, sparking a broader conversation on mental health among the elite sporting community.

"The sporting world needs to embrace mental health as part of the overall life condition, not to shy away from it," Towey said.

"And to use good mental health as first of all a stable platform for performance, but also to ensure that our athletes are looked after going forward for the rest of their lives."

Australian Olympic Committee president John Coates also paid tribute to Wooldridge.

"Stephen was an exceptional cyclist and Olympic champion who will forever be remembered," Coates said.

"He was always very giving of his time to the Olympic movement, helping out with fundraising efforts whenever he could for the Australian Olympic team over the years.

"Our deepest condolences are with his family, friends and all of those impacted by Stephen's passing."