The BBC World Service began broadcasting a new FM radio service in the Libyan rebel-held cities of Benghazi and Misrata on Thursday, the British broadcaster said.
BBC Arabic already operates on Libyan television and on short- and medium-wave radio, "and we are pleased to be extending our availability to FM radio," it said in a statement.
It will be in Arabic, with a "Newshour" programme in English once a day.
Liliane Landor, the BBC's controller of languages, said: "This year has been a very difficult one for Libyans.
"It is important for local people to have access to news and information that they can trust, and the BBC has experience of delivering that."
Libyan rebels from Misrata attacked the nearby town of Tuarga on Thursday in an effort to end the barrage of missiles that hits their home town almost daily, six months after they began fighting Libyan leader Moamer Kadhafi's regime.
Britain is among a number of countries taking part in a bombing campaign over Libya, with a UN mandate to protect civilians.