Egyptian voters are to take part in the third and final round of elections to the lower house of parliament.
People will head to the polls in nine provinces of the country - including the Nile Delta, the south and the tourist resorts of South Sinai - with voting taking place over several days.
The country's complex parliamentary poll is taking place in three stages and over three months.
Islamists are expected to dominate this first democratic poll in 60 years.
Tuesday and Wednesday's voters represent the last 15 million voters to cast their ballots in the first parliamentary polls since the overthrow of Hosni Mubarak last February.
Egypt's Supreme Council of the Armed Forces, which took power when Hosni Mubarak was ousted, has repeatedly pointed to the elections as proof of its plan to hand the reins to a civilian government.
But the third round takes place just days after authorities raided the offices of non-governmental organisations (NGOs) in the capital, Cairo.
Several US-funded groups seeking to promote democracy and political participation were among those targeted, with laptops and documents seized and employees questioned.
The interim government said the raids were part of a probe into illegal foreign funding of political parties. Its actions have been condemned by the United Nations, the US and rights groups.
The US-funded International Republican Institute (IRI) - one of the groups targeted - said it had been invited to monitor the election.
In the first two rounds, an unprecedented number of people voted, with turnout estimated at 62%.
Egypt's voting system is highly complex, with two-thirds of the 498 elected seats being decided by proportional representation and the rest by a first-past-the-post system.
The powerful Muslim Brotherhood, the country's best organised political movement is widely expected to triumph and has claimed the lead through its political arm, the Freedom and Justice Party (FJP).