Police are seeking dashcam footage of a motorists speeding along the Princes Highway on Sunday morning.
Leading Senior Constable Ian McNiven, of Koroit police, said a motorist driving a white sedan was clocked travelling at 160km/h in an 80km/h zone at Killarney shortly after midnight.
Police flashed their lights but the vehicle continued to head east at a rapid pace.
"Police lost sight of the vehicle shortly afterwards," Senior Constable Ian McNiven said.
He said a woman travelling from Port Fairy to Warrnambool reported the motorist speeding.
She said she feared the motorist would cause and accident.
"The vehicle has passed her just after going past the police vehicle," Leading Senior Constable McNiven said.
"She was only able to give a brief description of the vehicle so we're hoping to hear from anyone with dashcam footage."
Leading Senior Constable McNiven said it was incredibly dangerous to travel at such speeds.
"It's downright stupid."
The motorist would face immediate loss of licence and have their vehicle impounded if caught.
The incident comes after south-west police revealed they issued more than 400 tickets for speeding and other traffic offences as part of Operation Roadwise.
Nine drivers were caught drug driving, while eight were caught drink driving.
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