Zimbabweans were called back to vote on Thursday in 40 wards affected by delays during Wednesday's election and a prominent human rights lawyer alleged police were detaining about 40 civil society activists who had been monitoring the poll.

Both developments were likely to dent the credibility of the process in a country where the ruling ZANU-PF party has been in power for 43 years and previous elections have been marred by fraud and violence.

President Emmerson Mnangagwa was under pressure to deliver a clean election from foreign lenders and donors who have long shunned Zimbabwe due to ZANU-PF's record of economic mismanagement, human rights abuses and vote-rigging.

Mnangagwa, 80, took over from longtime strongman Robert Mugabe when he was ousted in a military coup in 2017. Mnangagwa won a disputed election in 2018 and is seeking a second full term.

His re-election bid comes against a backdrop of economic misery, with runaway inflation, a currency that has lost 85% of its value just this year and a joblessness crisis, leaving many Zimbabweans dependent on US dollar remittances from their relatives in the diaspora.

Mnangagwa's main challenger is the same as in the previous election: lawyer and pastor Nelson Chamisa, 45, of the Citizens Coalition for Change, who says he will resist any attempts by ZANU-PF to manipulate the election to stay in power.

Roselyn Hanzi, director of Zimbabwe Lawyers for Human Rights, said she had received information that police had detained about 40 members of two civil society groups late on Wednesday and raided their offices.

In posts on social media platform X, formerly Twitter, Hanzi said the activists were being detained without access to lawyers and had not been allowed to make any calls.

A police spokesperson declined to comment.

SKEWED PLAYING FIELD

After a significant number of polling stations in Harare and Bulawayo were hit by hours of delays on Wednesday, Mnangagwa ordered that voting should resume on Thursday in 40 wards.

The Zimbabwe Electoral Commission (ZEC) had blamed the delays on the late printing of ballot papers caused by court challenges, giving no further details.

Although the 40 wards make up less than 1% of the total, they include 11 wards in Harare, which has the highest number of registered voters and is a stronghold for the opposition.

Wards in Mashonaland Central, where the ruling party is traditionally dominant, and the battleground Manicaland were also affected.

Eldred Masungure, a lecturer in political science at the University of Zimbabwe, said the delays would jeopardise the integrity of the election and of the ZEC.

"It suggests that the ZEC was far from prepared. In the affected wards, we witnessed what amounts to an institutional disaster," he said. "That injury has been addressed somewhat but not everyone will have the time nor the resources to vote today."

Parliamentary results had been expected to trickle in on Thursday with the presidential result coming later, though well before a five-day deadline. It was unclear whether that schedule would be affected by the extended voting.

Independent analysts say the electoral playing field is heavily skewed in favour of ZANU-PF, which has a long history of using state institutions to manipulate the process to its advantage. ZANU-PF and the electoral commission have said the election would be clean.