A new Xbox One, vacuum and iPod were all left where they could be seen in cars parked in the town centre.
Police officers patrolled car parks at Morrison's supermarket, County Way and the Metrodome on Tuesday and in four hours found more than 50 cars which were either unlocked or unsecured in some way, or had valuables on display.
Det Ch Insp Mark Wilkie said one car was found with an Xbox One and other presents left on the back seat and was locked but had two windows down. Another car was left unlocked with an open handbag on the seat.
Other items left on show included Christmas presents (new and wrapped), cash, personal documents, sports equipment and bags.
He said the majority of items left on display were Christmas presents and urged people to make sure their cars were locked, windows were up and valuables were out of sight.
He added: "It only takes one of our prolific thieves to come across one of these cars and before you know it, several have been broken into.
"Please put things in the boot and out of sight. Leaving things on display is giving someone an early Christmas present who it is not intended for."
