The horse racing community has been rocked by the sudden death of trainer and master horseman Guy Walter early this morning.

Walter, 59, died of a heart attack while  at his Sydney home.

On Saturday, he celebrated a big-race win on Saturday when Streama won the Group One Doomben Cup.

“Like everyone in the racing industry, we are shaken by the tragic news of Guy’s passing,” Racing NSW chief executive Peter V’landys told Fairfax Media.  

“Guy was one of the most popular and humble trainers I have ever met.  I guarantee you would not find one person with a bad word for Guy; he was a very genuine, kind and respectful person.”

“Absolutely devastated… Speechless,” Kathy O’Hara, a jockey who rode many of Walter’s winners, posted on Twitter.

Walter trained 35 Group 1 winners and his horses have won more than $40 million in prize money.

He began his training career in 1980 on the New South Wales south coast before moving to stables in Sydney and Goulburn.

“This is a shockingly sad day,” Steve McMahon, chief executive of the NSW Trainers Association, said.

“Besides being a brilliant trainer, Guy was one of the nicest men you’ll ever meet.