Ofcom has begun a consultation on new price proposals for access to BT Openreach's telecoms services.
Broadband providers in the UK offer their services over BT's copper network, with the number of these unbundled lines increasing to five million over the last three years.
Openreach was set up under the instruction of regulator Ofcom, which required it to adhere to maximum prices set by the regulator for access to its network services.
Commenting on the consultation, Ofcom said: "The proposals cover Openreach's network services to homes and businesses.
"They are designed to promote continued competition in the provision of voice and broadband services and to ensure that Openreach has the appropriate incentives to invest in delivering the services required by its customers."
BT Openreach chief executive director, Steve Robertson, warned that it was "critical" that the firm be allowed to receive a fair rate of return on its infrastructure investment.