Tests by the German automotive organisation ADAC have concluded with warnings that owners with keyless car technology should be more vigilant, Auto Express reports.
The German vehicle experts tested 24 different vehicles with keyless technology from 19 different manufacturers.
The tests revealed thieves could bypass the central locking of every single vehicle using an "easily built" electronic device.
Keyless technology uses sensors to communicate with the key in proximity, allowing drivers to enter and start their vehicle without using the key.
A common way thieves operate with keyless technology is to have one follow the owner and use an electronic device to extend the range of the owner's key. A second waits by the car, using the signal to access the vehicle and start it.
A previous Auto Express report revealed how criminal gangs in the UK's capital are taking advantage of this technology.
Thieves were able to steal up to 17 cars a day in London in 2014, taking more than 6,000 cars over the course of the year.
Last year, a report revealed electronic immobilisers used by 26 manufacturers are vulnerable to hacking, meaning more than 100 models are at risk.
ADAC said: "Owners of cars with keyless locking systems should exercise increased vigilance in the storage of the key.
"It's the duty of all car manufacturers to get rid of this problem. It makes no sense that this more expensive locking system is way easier to break into than the normal one."
Do you own a car with keyless technology? Are you concerned by the report?