Police are warning the public about phone calls from people demanding payment to the energy company Nova.
Customers and non-customers of Nova have been targeted, with the caller threatening to cut off power if payment is not made, police said.
They are urging customers not to make payment until they have verified the call, which can be done by calling Nova on 0800 668 236.
Police are investigating the calls and would like to hear from anyone who believes they have been targeted.
Any information can be provided to police on 04 381 2000 or through Crimestoppers 0800 555 111.