Riverina Highway Patrol acting inspector Ben Smith said with the summer ahead, people tend to leave their engine on with the air-conditioner running or unattended while paying for fuel at service stations.

He said this was not only an issue for Wagga, but towns in the broader region where criminals check vehicles for keys and security.

"We had a number of pursuits lately with stolen vehicles in the area and found the keys have been left in the ignition," he said.

"We would like to remind people that criminals are opportunistic by nature."

Acting inspector Smith reminded residents they could pay fines of $116 each if the car is left unsecured, with the keys in the ignition and the engine running - a total of $348.

"It is not something we enforce often, but as I said it is an important problem we are facing and I don't want to be tasking my officers for this role," he said.

"We don't want to be having more pursuits of stolen vehicles because people have been silly enough to leave their keys in the ignition."