Police have had to rescue an elderly man who drove his mobility scooter along a 100km/h speed limit freeway in Melbourne's south east.

In footage shared to the popular Facebook page "Dash Cam Owners Australia", the 92-year-old can be seen attempting to merge into high-speed traffic along the Monash Freeway in Mulgrave on Friday afternoon.

The man refused to stop despite the appeals of concerned drivers.

The driver of the car filming shouted at the man to pull over.