Police are urging motorists to wrap their car keys in tin foil after scanning devices have been used to pinch vehicles.
Concerns have been raised that vehicles have been targeted in parts of Rushcliffe over the last few weeks.
Keyless car thefts are when thieves use a transmitter which acts like a car key.
Vehicles being taken include Mercedes, BMWs, Jaguars, Fords and Audis.
A spokesman for Nottinghamshire Police said: "We continue to take reports of vehicles being broken into or stolen with no apparent damage to the vehicle.
"This would suggest that people are leaving their vehicles unlocked, or the criminals are using scanners to pick up and boost a signal from the car key, enabling them to enter the vehicle and in some case drive off with it.
"Sophisticated scanning devices may be being utilised to obtain car key frequencies from vehicle keys stored within addresses.
"A lesser known fact is that some higher end vehicle keys using a keyless entry system can emit a signal up to 50 metres away so criminals may be able to pick up this frequency without being visible to the address, before approaching and stealing the car quickly.
"These scanning devices are not an illegal product and are readily available for purchase.
"The advice is to store vehicle keys inside a metallic container of some description which can block the signal emitted.
"Something as simple as a metal tin or even wrapping in tin foil could make the difference.
"Simply taking keys upstairs with you or storing at the rear of the house may not be enough.
"We have been successful in arresting offenders for these types of offences, but they are still occurring on a regular basis in Rushcliffe and elsewhere."
