A spokesman for the Zimbabawe Electoral Commission on Thursday said polling stations around the country officially closed at 7pm (1700 GMT), although voters who were still queuing within 200 metres of the stations would be permitted to cast ballots.
President Robert Mugabe says the polls are as free as any in the world, but they have been criticised as unfair by the opposition Movement for Democratic Change.
Also on Thursday, Zimbabwe arrested two British journalists on charges of covering the elections without state accreditation, an offence that carries a fine and up to two years in jail, police said.
A spokesman for the Sunday Telegraph in London said its chief foreign correspondent Toby Harnden and photographer Julian Simmonds had been arrested at a polling station near Harare.
"The Sunday Telegraph has had no communication with either of the journalists for several hours, nor from the Zimbabwean authorities. The paper is obviously concerned for their welfare and is endeavouring to secure their release," he said.
The polling was unfair, says the
opposition in Zimbabwe
The spokesman declined to comment on the Zimbabwean charges that the two were working without appropriate accreditation.
Earlier, Zimbabwe's Assistant Police Commissioner Wayne Bvudzijena said the pair had been arrested travelling with an opposition candidate in the parliamentary elections.
Mugabe's government has tough media laws barring foreign journalists from working in Zimbabwe on long contracts.
All journalists and media organisations must be accredited by a state-appointed commission.
"They came into the country as tourists, through Zambia, and they are being charged under AIPPA (Access to Information and Protection of Privacy Act) for practising as journalists without accreditation," said Bvudzijena.
Government officials say more than 200 journalists have been accredited to cover the elections, but dozens of others have had their applications rejected.