The Data Protection Commissioner has carried out raids on the offices of a number of mobile-phone text marketing companies.
The snap inspections were made in response to a large number of complaints made to the commissioner's office by members of the public.
It is illegal for a marketing company to contact anyone by SMS without their permission.
Commissioner Billy Hawkes is now examining data seized in the recent raids with a view to bringing prosecutions against any firm that sent unsolicited text messages.
He says he will come down hard on any company found to be breaking the law.