Thubiaan has maintained his unbeaten record over the big fences and put himself in line for a $300,000 bonus with victory in the Australian Steeplechase at Ballarat.

Since switching to steeplechasing after eight hurdle runs, Thubiaan has won three times this season.

He made his steeplechasing debut in the Von Doussa at Oakbank at Easter and carried on that winning form in the Brierly Steeplechase at Warrnambool early in May.

The Brierly success and Sunday's victory in the Australian Steeplechase (3400m) puts Thubiaan on track for the extra $300,000 if he can win the Grand National Steeplechase at Ballarat in late July.

Ridden by Martin Kelly, Thubiaan (1.90 fav) scored a half-length win over Dumosa ($10) with King Triton ($18) a long neck away third.

The Australian Steeplechase and Grand National Steeplechase have been moved to Ballarat while Sandown undergoes track renovations.

Trainer Eric Musgrove said Thubiaan was unlikely to have another jumps start before the Grand National.

"We won't need another run over fences, so we'll just have to look at the timing and make up our mind in a few days," Musgrove said.

It was a slogging finish and Musgrove was blowing just as hard as the winner post-race after barracking hard as the three placegetters made their way to the finish.

Musgrove said the longer term plan for Thubiaan was to head to Japan next year to follow in the footsteps of Karasi who the trainer took to three wins in the world's richest steeplechase, the Nakayama Grand Jump.

"We're still thinking about Japan," Musgrove said.

"We want to season him a bit more and get him through this season and look to that later.

"He couldn't do any more than what he's done at this stage."

Kelly has been aboard Thubiaan in all three of his steeplechase victories and was confident of success a long way from home.

"I knew he would stay all day and it just came down to whether he could fight the others off or not," Kelly said.