Leading Senior Constable David Rook said a 74-year-old Macarthur man was clocked at 170km/h on the Port Fairy-Hamilton Road, north of Macarthur, about 10am Tuesday.

"That speed is just absolute madness," he said.

"The motorist said he was unaware he was travelling that fast which is scary. He did admit that he was speeding but didn't know by how much so it is particularly concerning."

Leading Senior Constable Rook said there was no traffic, the road was in good condition and the weather was fine.

"But even at that sort of ridiculous speed, if something had happened it wouldn't have ended nicely," he said.

"This sort of driving behaviour is very concerning given the amount of collisions, particularly fatalities, that we have had recently.

"The fact that motorists continue to travel at these types of speeds... I'm just stunned."

The man's Subaru Outback was impounded for 30 days at a cost of $1100.

He was also summonsed to appear in Hamilton Magistrates Court at a later date.

Fatal accidents have occurred near Macarthur, Noorat, Allansford and Woorndoo in the past couple of weeks.

There were also serious accidents which resulted in a bike rider at Dennington and a woman driver in her 20s on the outskirts of Hamilton being flown to Melbourne hospitals in critical conditions.

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