The crash has prompted the South West Coast MP to renew calls for the Woolsthorpe-Heywood Road to be upgraded.

However Sergeant David Walkley, of Port Fairy police, said the condition of the road was not a factor in the crash.

"This was a dual lane part that was fairly reasonably resurfaced. It's not because of the road surface that this collision has happened," Sergeant Walkley said.

He said the Warrnambool Highway Patrol was investigating the crash.

"Drivers of all vehicles need to drive according the road and the conditions. They need to take heed of the speed advisory signs that indicated the suggested speed to get around a corner," he said.

He could not confirm how many of the 60 cattle had died, but said at least 15 were ejected from the top deck of the truck when it rolled.

Ms Britnell said she had written to Victoria's Road Ministers "consistently" over the past four years asking for large sections of the road to be upgraded.

"This time it was cattle, but next time it could be a person," Ms Britnell said.

"I've spoken to truck drivers who now simply refuse to drive on the road, even if it's the quickest route, because it's too dangerous."

A government spokesman said the incident would be investigated.

"This is obviously a distressing incident for everyone involved, including emergency services responding to the scene," he said.

"After all incidents there is an investigation to determine whether any road improvements need to be made."

There have been three crashes resulting in serious injuries and three crashes resulting in minor injuries, in the five years to June 2019 on the road between the Warrnambool-Caramut Road and the Hamilton Port Fairy Road.

Regional Roads Victoria has introduced temporary reduced speeds for some sections of the road and completed about five kilometres of minor patching and surfacing work in the last two years.

"We have already completed some interim repairs on Woolsthorpe-Heywood Road and are currently monitoring the road for any further improvements," RRV's south-west director Emma Miller-Olsen said.

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