Eager voters cast ballots on Saturday in Libya's first free national elections for decades after the ouster of dictator Muammar Gaddafi, but polling was disrupted in the troubled east.

In Tripoli, voting got underway with queues of people keen to elect the General National Congress. "Words cannot capture my joy, this is a historic day," said Fawziya Omran, one of the first women in line to cast her vote in the capital.

Voters in Tripoli turned up in the capital draped in black, red and green flags -- the colours of the revolution that toppled Gaddafi in 2011-- while mosques blasted chants in the praise of God. Joy was also palpable in the eastern city of Benghazi, which was the cradle of the uprising.

However, protesters who demanded greater representation for the east in the 200-member Congress assembly, forced the closure of several polling stations elsewhere in the tense region. Some voting centres were shut in the eastern city of Ajdabiya, where a depot containing electoral material was torched this week.

Another centre was disrupted at southeastern oasis, including Jalo and Ojla, after federalism supporters prevented a plane carrying polling material from taking off. The elections were boycotted in Quba.

A senior official in Tripoli dismissed reports that the elections could be delayed in those areas, stressing they were working towards a solution.

Interim leader Mustafa Abdel Jalil, voting in his eastern home town of Al-Bayda, said the situation there was "excellent" and hoped Benghazi would stay away from such problems and that the voting would go ahead smoothly.