The scheme, to launch in July, should boost TPS registrations, which are at an all-time high of 7.7 million. TalkTalk, the landline arm of Carphone Warehouse, already offers customers the opportunity to register.
BT wouldn't comment on the initiative, but the Direct Marketing Association (DMA) said it had been approached by "senior BT management" regarding TPS registration for its customers.
Tessa Kelly, DMA director of compliance operations, said BT had asked about "improving the efficiency of signing up its customers to TPS. We're discussing with them how it can be improved." She said the DMA had sought assurances on the matter.
"There are some points we drew to their attention and are satisfied they're being addressed, such as that consumers are given full and fair information to make the decision on TPS and that it isn't an automatic process," Kelly added.
BT says it is keen to give its customers control over how they're contact-ed. It said its BT Privacy Online modem-protection service, unveiled in May for users seeking to safeguard against un-authorised diallers, has been a success.