Renowned bloodstock agent, journalist and long-serving Thoroughbred Breeders' NSW committee member Les Young has died suddenly, aged 76.

A racing industry all-rounder, Young dedicated his time and passion to several racing and breeding pursuits during an extensive career.

A foundation member and vice president of the NSW Racehorse Owners' Association, Young was well regarded for having a keen eye for a thoroughbred.

He managed Sydney premiership-winning trainer Brian Mayfield-Smith's Nebo Lodge during its period of prominence, helping Mayfield-Smith end Tommy Smith's 33-year reign as champion trainer.

Representing breeders on the Racing Industry Participants Advisory Committee, including a term as chairman, Young was a past president and life member of the Federation of Bloodstock Agents of Australia.

He was also a regular contributor to several industry publications, including The Sportsman.

Racing NSW boss Peter V'landys said Young was a passionate advocate for the industry and would be missed.

"I'm shocked and devastated at the passing of Les Young. He was one of the real gentlemen of the turf,'' V'landys said.

"Les will be greatly missed and our condolences to his family."

Stuart Lamonte, president of Thoroughbred Breeders'NSW, said Young would be remembered for bringing people into racing.

"Among Les Young's many talents was the ability to encourage young people in a new career or a new venture, he made time for the breeder with a single mare just as he did for the high rollers,'' Lamonte said.

"He was hugely influential in the careers of some of the greats of the Australian turf such as Emancipation and Snippets, but even more influential in the many friends he made and people he mentored.''