Hunter Valley police are urging residents to lock their cars and secure their number plates after a recent increase in thefts from vehicles across Cessnock, Kurri Kurri and Branxton.
Most of the incidents happened in residential streets and home driveways, with wallets, credit cards and number plates among the items stolen.
Hunter Valley Police District crime manager Detective Inspector Matthew Zimmer said theft from vehicles - particularly number plate theft - is an "ongoing problem" in the Cessnock area.
"Police believe the stolen number plates are being put onto other vehicles to commit other crimes," he said.
"The things that are being stolen from cars are being used in fraud offences, and also open up the potential for identity theft."
Detective Inspector Zimmer said police have regular operations to address these issues, and they appreciate any assistance from the community.
"Our dedicated team is very proactive in attempting to disrupt this type of criminal behaviour," he said.
"If you do see anything, please let us know so we can investigate it."
Some of the stolen property was taken from unlocked vehicles, and police are urging car owners to always lock their vehicles and remove any valuable property.
Number plates can be secured with anti-theft screws that can be bought at most auto parts stores and some hardware stores.
According to the Bureau of Crime Statistics and Research, 436 steal from motor vehicle incidents were recorded in the Cessnock LGA in the 12 months up to September 2019 - 1.5 times the state average (per 100,000 people).