'No idea' Melbourne teen clocks 170km/h

A teenager caught driving 170km/h on a Melbourne freeway later told police he had no idea how fast he was going.

The 19-year-old from Mill Park sped past officers conducting a laser-gun speed check in a 100kmh-zone on the Metropolitan Ring Road, late on Friday.

He told them he was oblivious to his speeding, and is expected to be charged on summons.