Gardaí have released figures on the number of theft from vehicles offences that have occurred in each garda division between January 2016 and December of this year.
It is part of their Park Smart campaign warning vehicle owners not to leave the cars and vans unlocked.
Cork, in particular, has been hit by a spate of such offences in recent years.
In the Cork City division, there were 2,249 thefts from vehicles over the past four years, 687 in Cork North and 314 in Cork West.
Many estates in the city and county have seen people going from driveway to driveway checking all vehicles before finding an unlocked one and stealing any valuable contents inside.
Figures show that €30.6 million worth of items such as tools, cash, sunglasses, electronics and jewellery have been stolen from vehicles over the past four years.
In that time period, 46,582 vehicles were broken into. In 8,157 of these cases, the vehicle was reported to have been unlocked.
Of the 12,343 vehicles broken into outside homes, 3,833 are reported to have been unlocked – that’s almost 1 in every 3.
The analysis also shows that the most common location for these thefts are in driveways and that most common times are between 12 midnight and 6am. Such thefts are happening throughout the country.
Gardaí are appealing for all vehicle owners to ensure they lock their vehicle no matter where it is parked. Do not store valuables in it, but if you do have to, keep them out of sight.
Crime Prevention Officer Sgt James O Donovan based in West Cork said: "What is happening now is criminals will go around areas like housing estates and streets where lots of cars are parked up and they will try every car door because they know we are leaving some of them unlocked. Let’s not make it easy for these criminals, make sure to lock your vehicle every time."
"Wherever you park your vehicle, we would always advise you to take your property with you and ensure the vehicle is locked, alarmed and parked in a secure, well-lit location. Try not to leave any valuables in the car whatsoever.
Last week, the chairman of Cork City FC posted CCTV footage from his home off the Blarney Road where individuals were trying vehicles to fund unlocked cars.
"Sometimes it is impractical to remove tools and equipment from vehicles. In these cases, owners should take extra steps to ensure the safety of their property."
"Additional locking mechanisms to vehicles should be fitted. Consider a monitored vehicle alarm and tracking devices for valuable property. Try marking and photographing your property and take a record of serial numbers, makes and models."
"You can download a property register booklet on www.garda.ie This can not only deter a criminal from taking your property, but it means if we recover the stolen items we can get them back to you.”
An Garda Síochána’s advice surrounding any vehicle keys would always be to avoid leaving them on the hall table or near a door/window where they could be easily taken.