A spike in car thefts in Mornington has prompted police to go around opening car doors in the suburb.
Senior Sergeant Mark Donaldson said police discovered 20 unlocked vehicles in the area last night and early this morning.
Police put pamphlets warning about the hazards of leaving vehicles unlocked inside and then locked the doors, he said.
"We're really just asking that people help us out a bit and start locking their vehicles."
