Leading syndication company Star Thoroughbreds has announced a change in direction with Chris Waller to be the trainer of all yearlings bought this year.

Gai Waterhouse has been the exclusive trainer of Star Thoroughbreds horses since Denise Martin established the company 20 years ago.

Martin said in a statement on Sunday all horses currently trained by Waterhouse would remain in her care but all new acquisitions would go to Sydney's premier trainer.

"After a lengthy and extremely successful association with Gai Waterhouse Racing, Star Thoroughbreds announces today the beginning of a new business relationship with Chris Waller Racing," Martin said.

"All yearlings purchased this year by Star Thoroughbreds will be trained by Chris Waller.

"The many horses which Gai currently trains for Star Thoroughbreds will continue to receive the expert care and attention, characteristic of the Hall of Fame trainer and will also continue to wear the famous purple and white stars, Star Thoroughbred's colours."

Martin said she maintained a personal relationship with Waterhouse and the decision was in the interests of her business.

"Gai is one of the world's greatest ever racehorse trainers and her record breaking achievements are legendary," she said.

"I have an excellent personal relationship with Gai and her team and I look forward to continued success with the large number of horses Gai currently trains for our Star owners.

"My decision is purely business based and I'm looking forward to the next challenge in the life of Star Thoroughbreds."

Among the horses Martin has syndicated are 2008 Golden Slipper winner Sebring, multiple Group One winner Theseo and 2012 Magic Millions winner Driefontein.