Porn dialers reroute a dial-up connection away from the Internet service provider's number and through a premium-rate phone number, typically to a company based overseas.
The Independent Committee for the Supervision of Standards of Telephone Information Services, which regulates premium-rate telephone services in the U.K., says disputed bills have topped $3.6 million, or £2 million.
A brochure from the ICSTIS explains how to distinguish legitimate dialer services from those that reroute dial-up connections by tricking consumers.
It also explains how consumers can lodge a complaint if they have been duped into downloading a dialer.
ICSTIS has introduced a licensing program for companies that operate such dialers, with on-screen guidelines before the Internet call is rerouted.
Since announcing a crackdown on rogue internet dialers, British telecommunications company BT says it has blocked 1,000 numbers allegedly associated with the problem.
The telecom said it has begun blocking Internet traffic to both U.K. and international numbers it suspects of being used by the porn dialers.
BT said it has now dealt with 45,000 cases where customers have fallen victim to a rogue dialer, with a further 9,500 cases waiting to be resolved.