Police have issued a warning after five industrial estate units in the Caerphilly and Bedwas areas were broken into in just two months.
Criminals forced their way into some premises but have also gained entry into some insecure units.
Local Crime and Disorder Reduction Officer PC Stuart Lewis said: “It is essential that all is done to deter a would-be offender from attempting to break in. There are many ways to protect against intruders, and site security should be regularly reviewed.
“As well as measures such as Intruder alarms, camera surveillance and security guard patrols which can be expensive, owners should also consider other low cost and common sense measures which can be put in place to protect property.
“Should unit owners have any specific concerns I would advise them to contact me further advice or guidance firstname.lastname@example.org.”