BT is pushing up charges by £4.50 per quarter for customers who pay by cash or cheque.
The increase covers the extra cost of processing payments from people who do not pay by direct debit, the telecoms giant said.
It will offset the rise by dropping line rental by £3 per quarter for non-direct debit customers.
The firm is also putting up its late payment charge from £5 to £7.50.
Five million customers
More than five million BT customers will be affected by the increases when the changes come into force on May 1, a spokesman for the firm said.
Non-direct debit customers who use both BT landline and broadband services will have their rental charge cut by 50p per month.
A BT spokesman said: ‘Charges for customers not paying by direct debit are standard across the telecoms industry. BT’s charges are quite modest compared to other companies.’