Victoria's road policing assistant commissioner Glenn Weir was detected travelling eight kilometres over the limit on Manningham Street in the inner-Melbourne suburb of Parkville at 10.55am on February 29.

A mobile speed camera detected Mr Weir speeding in an unmarked police car while travelling to a meeting, Victoria Police said.

"I take full responsibility for this error and am mortified it has occurred," Mr Weir said.

"I've spent my entire career advocating for road safety and this incident proves nobody is immune from making a mistake on the road," he said.

Mr Weir said he received notification of the fine on March 22.

He thought he was driving at 58km/h in a 60km/h zone, Mr Weir said in a police statement.

"No matter how far over the limit, all speeding is unacceptable," he said.

"For someone in my position this is especially true.

"I am truly sorry."

Despite being eligible for a warning due to his driving record Mr Weir said he would to pay the $337 fine.

The senior policeman would also lose one demerit point, police said.