Police detect driver allegedly speeding at 251km/h

Police say they are 'lost for words' after detecting a driver allegedly travelling at 251km/h in Melbourne's northwest on Easter Sunday.

Officers say they detected the white Volkswagen sedan allegedly travelling at more than 140km/h over the 110km/h speed limit on the Calder Freeway near Woodend at 12.30am.

The vehicle was intercepted in Kyneton a short time later, where the driver, a 42-year-old Hallam woman, was also seen to be on her phone.

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The woman's car was impounded following the incident.

The 42-year-old is expected to be charged on summons with numerous offences including conduct endangering life, drive at dangerous speed and using a mobile phone while driving.

The detection is part Operation Compass, the state-wide road policing operation during the high-risk Easter holiday period.

Police are targeting impaired driving, speed, distraction and fatigue in high-risk areas throughout metropolitan Melbourne and regional Victoria.

Operation Compass concludes at 11.59pm on April 25.