In a sport where danger is ever-present, the death of popular young jockey Nathan Berry from a rare illness has rocked an industry used to taking hard knocks.

After becoming ill in Singapore on March 18 where he had just begun a short-term contract, 23-year-old Berry was brought home to Sydney where he died on Thursday from NORSE syndrome, a little-known condition connected to epilepsy.

His identical twin and fellow rider Tommy has described the death of his brother as losing a part of himself.

For his young bride Whitney, Nathan's death has brought a sudden and cruel end to the life they planned together.

"He just loved me unconditionally. He moved heaven and earth for me," Whitney Berry told Network Ten.

"It's hard to comprehend that he's not going to be here with me but I hope that he's up in heaven watching over me and walking every step with me."

The two were married in early February, a few weeks after Nathan claimed the biggest win of his career in the $2 million Magic Millions at the Gold Coast on Unencumbered, a colt he should have been riding in Saturday's Golden Slipper at Rosehill.

Unencumbered will be ridden by Craig Williams in the $3.5 million Golden Slipper, a race won by Tommy Berry on Overreach a year ago.

Tommy, Whitney's father Glyn and her brother Chad, will all ride at Rosehill to honour Nathan.

At Tommy's request, a minute's silence will be held after the renamed Group Two Nathan Berry Tulloch Stakes.

He and his fellow riders will wear royal blue ribbons instead of the traditional black armbands to recognise Nathan's favourite colour which makes up a large part of Unencumbered's silks.

Racing NSW chief steward Ray Murrihy said measures were in place to protect the family and a counsellor would be available to all jockeys throughout the afternoon.

"In racing we are aware of the dangers," he said.

"But this feels like we have been ambushed.

"The Berry twins are fine young people and over the past weeks, Tom Berry has shown a maturity beyond what you would expect from a 23-year-old."

Champion jockey Jim Cassidy will not ride in the Golden Slipper due to suspension but will be on hand to talk to his colleagues during the day.

"I feel like my heart's been ripped out," Cassidy said.

"It's a big day tomorrow when he should have been there.

"It will be a tough day in the (jockeys') room."

Christian Reith, a riding colleague and close friend who flew to Singapore this week to be with his mate, said he would ride to celebrate Nathan and to honour his family.

"We shouldn't be crying on their shoulders, they should be crying on ours," Reith said.

"I feel blessed that Nathan allowed me to be his friend.

"He encouraged a lot of people and he still will.

"We'll ride in tribute to Nathan for the rest of our lives."