The records might show Mark Newnham will saddle his first Golden Slipper runner at Rosehill, but that belies his experience with the worlds' richest race for two-year-olds.

Newnham took out his trainer's licence less than a year ago after severing ties with the Gai Waterhouse stable after two decades.

After retiring as a Tulloch Lodge jockey, Newnham became Waterhouse's right-hand man and was involved in the preparation of three of the trainer's six Golden Slipper winners - Pierro (2012), Overreach (2013) and Vancouver (2015).

He knows what it takes to win the race and with the wet track introducing a new element, Newnham believes Diamond Tathagata is a realistic chance to showcase his stable on Saturday.

"I didn't expect to have a Slipper runner with so few horses to work with," Newnham said.

"He was actually my first horse.

"We have built up with a few more young horses from the sales this year.

"He's shown above average ability and that he can handle the wet track and some of the others might not be able to.

"When I was with Gai we had three Slipper winners and I know what it takes to get a horse there and then anything can happen."

The Rosehill track was rated a heavy 9 on Friday afternoon following strong winds and several hours without the rain that has plagued Sydney all week.

Diamond Tathagata has had two starts, both on heavy tracks, prompting punters to back him from $61 to $35.

He finished second on debut to She Will Reign in the Inglis Nursery in December and gave Newnham his first major win in the Group Two Skyline Stakes to seal a Slipper berth.

Long-time favourite She Will Reign is now on the third line of betting at $6.

Magic Millions Classic winner Houtzen is steady at $4.40 with Blue Diamond Stakes winner Catchy now second-elect after being backed from $7 to $5.50 with the TAB despite her lack of any wet form.

The Australian Turf Club's general manager of tracks, Lindsay Murphy, said on Friday he was confident the meeting would go ahead although more rain is expected in Sydney.

"It hasn't been a bad day. We've had a lot of wind and not much rain," Murphy said.

"The forecast is for more rain but not a lot at Rosehill.

"The meeting will definitely go ahead as planned unless we get more rain on the day but hopefully it's mostly coastal."