Detective Sergeant Dale Menzies, of the Colac crime investigation unit, said there were a number of theft of motor vehicles since the start of 2020 in the Colac/Otway area.

"It is a concern that many of these vehicle thefts still involve unlocked vehicles with keys left inside," he said.

"Similarly, unlocked motor vehicles account for the majority of the theft from motor vehicles reported for the same period."

Detective Sergeant Menzies said nearly 80 per cent of theft of motor vehicles reported in Colac/Otway involved unlocked vehicles with keys left in the ignition, floor well or door console.

"Several offences occurred within the Colac township however there is a trend for offender/s to target farm vehicles as it appears common practice for owners to leave vehicles unlocked with the keys inside," he said.

"Offending has occurred in outer towns including Birregurra, Beeac, Cressy, Coragulac, Beech Forest, Warncoort, Gerangamete and Kawarren."

Detective Sergeant Menzies said the majority of stolen vehicles were located however some were damaged and two were destroyed by fire.

"This is not a new issue but it appears many members of the community still believe that because they are living in quiet country towns or farming areas that they are unlikely to be victims," he said.

"The prevention strategy is an easy one - at all times, lock your vehicles and remove your valuables from the vehicle," he said.

"It doesn't matter if you are in a township or on a property, don't give an offender an easy opportunity."

Anyone with information should contact Colac police or Crime Stoppers.

Have you signed up to The Standard's daily newsletter and breaking news emails? You can register below and make sure you are up to date with everything that's happening in the south-west.