The Hong Kong Derby has attracted Australians Craig Williams and Dwayne Dunn for a hit and run mission with ex-pat Tim Clark also looking to further bolster his reputation.

Williams, who starred with four winners at Flemington on Saturday, will ride Wah May Star while Dunn will be aboard Endowing in Sunday's 2000m feature at Sha Tin.

Endowing is one of two runners trainer John Size who also has It Has To Be You who will be ridden by Clark who steered him to victory last month.

Clark was back in Australia on Saturday to ride in the Group One Newmarket Handicap at Flemington.

He finished fourth on Undeniably but bagged a Group Three winner on the day when he produced a rails-hugging ride to get Bonaria home.

Clark said he was looking forward to the Derby, one of the biggest as he attempts to claim his biggest win so far since moving to Hong Kong in 2011.

It Has To Be You caused a boilover in last month's Group One Classic Cup (1800m), the second leg of the Hong Kong Triple Crown for four-year-olds.

"Obviously I link up again with It Has To Be You who won the lead-up," Clark said.

"It was a bit of a farcical-run race but he did nothing wrong and won well. If he draws a low gate he's got to be a good chance again."

The former champion Sydney apprentice is having a fine season in Hong Kong, sitting fifth on the premiership in addition to claiming his breakthrough Group One trophy.

He said his time in the competitive racing scene so far had been rewarding.

"Obviously it's tough and it's the sort of place that you can never think you are going well," Clark said.

"You've got to keep yourself grounded and just keep working at it. But things are going well and I've just got to keep focused and keep working at it."

The nominal favourite for the Derby is Akeed Mofeed, one of three runners for Richard Gibson.

Perennial premiership winner Douglas Whyte rides Akeed Mofeed while Olivier Douleuze will be aboard stablemate Gold Fun and Umberto Rispoli has been confirmed for Mizani.