The Caulfield Cup is shaping as the likely target for New Zealander Volkstok'n'barrell who has his next spring start in the Turnbull Stakes.

The four-year-old will race on an eight-day back-up in Sunday's Group One 2000m race at Flemington and co-trainer Chris Gibbs believes the gelding has improved again from his fifth placing in the Underwood.

Volkstok'n'barrell was third-up in the Underwood last Saturday and Gibbs said the Rosehill Guineas winner had taken time to reach peak fitness this spring.

The horse holds nominations for the Caulfield Cup and Cox Plate but it is the 2400m handicap that looms as the most likely goal.

Volkstok'n'barrell has 53.5kg in the Caulfield Cup with the Cox Plate run under weight-for-age conditions a week later.

"I think we're definitely leaning towards the Caulfield Cup, probably because of the weight," Gibbs said.

"Unless he did something spectacular on Sunday, we're definitely looking at running in the Caulfield Cup."

Gibbs said the four-year-old has come through the Underwood very well, paving the way for connections to accept for the Turnbull.

"I think the horse has improved again with the run," he said.

"It's a shame you've got to back up but he shows us that he's pretty tough and he's improved.

"I think he's going to cope with it all right."

Volkstok'n'barrell has been ridden by Craig Williams in his past two starts but Williams had already been booked for Gust Of Wind on Sunday.

Opie Bosson has picked up the Turnbull ride on Volkstok'n'barrell, a horse he knows well having ridden rival Mongolian Khan to wins over Volkstok'n'barrell in the New Zealand and ATC Australian Derbies.

"He's a champion jockey. He knows how to ride over here and knows how to ride in the big races and we're happy to have him on," Gibbs said.

Gibbs is happy with barrier eight noting a number of the favourites have drawn wide.