Libya's electoral commission announced Sunday it was scrapping the results from 24 polling stations due to fraud in a parliamentary election contested at 1,600 stations in June.
An investigation has been launched and those responsible for the alleged fraud will be put on trial, said commission chief Imed al-Sayeh.
Sayeh was speaking at a news conference to announce preliminary results for the June 25 election, which was marred by a poor turnout, violence and the murder of a leading women's rights activist.
Authorities had hoped the poll would ease the political turmoil and rising lawlessness gripping Libya since its 2011 revolution which ousted longtime dictator Muammar Gaddafi.
But only 42 percent of 1.5 million registered voters turned out, according to the commission, with several MPs in the 200-seat parliament elected with less than 1,000 votes.
Sayeh said the final results should be known July 20, but would only cover 184 seats.
Polling for the remaining 16 seats would take place at a later date, after voting was not held in several constituencies due to violence.
The future makeup of parliament will only be known after the formation of political blocs, since the vote was open only to "individual candidates" and lists were barred.
Commentators say liberals will fill most seats in the new parliament, unlike the former assembly which was dominated by Islamists.
The outgoing General National Congress, elected in July 2012 polls, had been mired in controversy and accused of monopolising power.
The crisis came to a head when members of the GNC in February, when its term was due to expire, decided to extend their mandate until December.
That sparked street protests and forced lawmakers to announce the June election.