Champion harness racing trainer and reinsman Gavin Lang has died aged 61.

Lang was diagnosed with a rare type of lymphoma in September last year and had been undergoing treatment in Melbourne.

He drove his first winner in June 1975 and in 2017 became the second Australian driver to reach 6000, with Chris Alford the other.

Among his biggest wins were two Inter Dominion Trotting championships, the Breeders Crown, Chariots Of Fire, Australian Pacing Gold, Vicbred Super Series and NSW Derby.

He grew up in harness racing and followed his father Graeme into the sport.

Lang was an instinctive driver renowned for split-second decisions.

"It becomes second nature to you, making moves is a reflex action," Lang once said.

"You seldom think about it, it just comes to you. It is hard to explain why that happens. You do everything on instinct. If you have to stop and think whether to make a move, by the time you are done thinking it's generally too late."

Lang is survived by his wife Meagan and daughters Danielle and Courtney.