Cambridge Stud boss Sir Patrick Hogan is keeping Tavistock's 2016 service fee under wraps but it's likely after Day One of The Championships at Randwick, he will revise it upwards.

Triple Group One winner Volkstok'n'barrel runs in Saturday's Doncaster Mile but more attention will be on Tavistock's three-year-old son Tarzino who is odds-on to add the Australian Derby to his Victoria Derby in the spring.

Mick Price has an affinity with Tavistock having trained the future stallion in a four-start Australian campaign, and is enamoured of his progeny.

But the trainer may have to go higher than the $60,000 he put his hand up for at the Magic Millions sale to secure Tarzino.

"I might not be able to afford them soon," Price said.

"They are lovely big, strong horses and they work well with the New Zealand mares.

"I had Tavistock for four starts when he was a three-year-old. He won a race but had trained off before the Caulfield Guineas.

"He went back to New Zealand and won a couple of Group One races and let down into a magnificent horse."

Rosemont Stud have bought a share in Tarzino who races in their colours as does the Donna Logan and Chris Gibbs-trained gelding Volkstok'n'barrel.

"Rosemont have a share but not the standing rights which will be decided in the future," part-owner Price said.

Tarzino will be having his final start as a three-year-old in Saturday's Derby (2400m) with the major spring Cups in mind.

He is at $1.90 to win the Derby and, although he toyed with the Rosehill Guineas field, Price is taking nothing for granted.

Godolphin colt Tally is a newcomer to Group One racing but has won four consecutive races with his last start bringing a Group Two victory over Australian Guineas winner Palentino.

Tally and VRC Oaks winner Jameka are regarded as Tarzino's major threats with both on the second line of betting at $6.50.

"Tally is a horse on the way up and if he stays, he is a danger," Price said.

"But there are no negatives with Tarzino."

Two of New Zealand's Derby hopes, What's The Story and Tavago, another son of Tavistock, are expected to leave for Australia on Thursday night after being grounded because of a mechanical fault with their plane.