Chief Supt Ger Dillane, who is in charge of policing that region, said some incidents had occurred recently which led gardaí to believe a gang is watching banks.
He said people who had withdrawn large sums of cash had put the money into the glove compartment of their cars after leaving the banks. When they later stopped at a petrol station or shop, the gang got into the car and stole the money.
The garda said they are liaising with banks and looking at CCTV footage in an effort to identify the culprits.
He told a meeting of the Cork County Joint Policing Committee (JPC) that car owners are being lax about locking their vehicles as thefts from cars were up nearly a third in the past three months, compared to the same period last year.
Reported theft of property from vehicles increased from 137 to 177.
Chief Supt Dillane said when he arrived for yesterday’s JPC meeting in County Hall he noticed a car left in the car park which had all four doors open and a lot of valuable items inside.
Chief Supt Michael Finn, who is in charge of policing Cork City, said he had been alerted by a neighbour about a four-man gang who were trying to steal from unlocked cars in his own estate.
The men were subsequently arrested for a spate of thefts from unlocked vehicles in the Douglas and Glanmire areas.
Chief Supt Dillane said people needed to be more careful and ensure their car doors are locked at all times.
He said the gang was simply walking into estates and trying car doors, many which were left open, even at night.
Theft of vehicles was down from 71 to 56 over the comparable periods and interfering with a vehicle dropped from 18 to 11.