Libya's General National Congress elected Ali Zeidan, a long-time opponent of deposed dictator Muammar Gaddafi, as prime minister on Sunday, the assembly's chief said.

"Ali Zeidan is elected prime minister and is asked to propose a cabinet within two weeks," Mohammed Megaryef, president of the national assembly, said in remarks broadcast on television.

Benefitting from the backing of the liberal coalition in the 200-seat assembly, Zeidan won 93 of the votes cast, trumping the 85 garnered by the only other candidate, local government minister Mohammed al-Hrari.

Zeidan replaces Mustafa Abu Shagur who was dismissed as prime minister last week.

A former career diplomat, Zeidan defected in 1980 while he was serving at the Libyan embassy in India, and spent the next three decades in exile.

He was a member of the opposition National Front for the Salvation of Libya, established in 1981 by dissidents abroad, before becoming a Geneva-based advocate for human rights in Libya.