Shaun Guymer kicks off a new phase of his riding career at Flemington on Saturday.

But he will do so with a heavy heart following the death of his close friend Nathan Berry.

The apprentice made the move to Melbourne from Sydney last Sunday to begin a Victorian stint with his boss Peter Moody.

The 21-year-old formed a close bond with jockey twins Nathan and Tommy Berry and fellow rider Christian Reith in Sydney in recent years.

Despite the trauma of Nathan's death from a rare illness on Thursday, Guymer said he would honour his commitments at Flemington as his friend would have wanted.

"You know that movie 'The Hangover', we used to joke around (we were) the wolf pack," an emotional Guymer said.

"Those three boys I would say would nearly be the closest buds you could ever have."

"Nathan would kick you in the arse and tell you to get going and keep pushing forward so you've got to do it."

"He wouldn't want it any other way," Guymer said.

Guymer said he had often sought the counsel of Nathan Berry and paid tribute to the young jockey the Australian racing industry is mourning.

"Even if he was struggling himself, he always had time for me. And that goes for other people as well. He always had time for other people," Guymer said.

"He's a very well-loved and respected guy."

Guymer is booked for Genuine Spin and Cosmic Causeway for Moody. He has been with the stable at Randwick since last September and said his move south could be open-ended depending on how things pan out.

Originally from Goulburn, the apprentice made an immediate impression when he first moved to Sydney a few years ago but admitted things had "got a bit stale" more recently with limited opportunities for apprentices in Sydney.

"I've got a really good boss behind me who supports me and has given me this opportunity," Guymer said.

"Now all I need to do is get on the right horse and give it a really good crack.

"It's the right time down here for kids (apprentices) during winter."