Four cars have been searched for valuables in Hamilton at night but little was taken.
Hamilton police Sergeant Simon Bourke said all four vehicles were unlocked.
"It's timely to remind people to lock their cars and put valuables out of sight," he said.
"The thefts happened in the May Street and South Boundary Road area of Hamilton overnight Sunday.
"It's the same old message from police - lock your vehicle.
"Nothing of great value was taken but it was noticeable that the cars had been rummaged through," he said.
Anyone with information about the thefts is requested to contact the Hamilton police station or Crime Stoppers on 1800 333 000.
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