Polls have closed and counting is under way in Zimbabwe’s first general election since long-serving ruler Robert Mugabe was ousted.

Voter turnout was 75 per cent, it was reported, in what is expected to be a tight contest between the incumbent Emmerson Mnangagwa and main rival Nelson Chamisa.

Many citizens of the African nation are anxious for change after economic and political paralysis during the nearly four-decade rule of 94-year-old Mr Mugabe who was ousted in a military coup.

Thousands of election monitors fanned out across the country to observe a process that the opposition said is biased against them, despite assurances from the electoral commission.

The two main contenders are president Emmerson Mnangagwa, 75, a former deputy leader who took over after Mr Mugabe stepped down last year, and 40-year-old Nelson Chamisa, a lawyer and pastor who became head of the main opposition party a few months ago.

Opinion polls gave Mr Mnangagwa, who heads the ruling Zanu-PF party, a narrow lead over Mr Chamisa, the opposition Movement for Democratic Change (MDC) leader, according to reports.

The official result has to be announced within five days but there will likely be an indication of the outcome on Tuesday.

Mr Chamisa yesterday claimed victory was “certain” as millions cast their vote. He told cheering crowds “the people have spoken” after voting at a primary school in the country’s capital Harare.

He was welcomed with greetings and shouts of “our new president”, despite the indications of opinion polls giving Mr Mnangagwa the edge.

President Mnangagwa in a surprise speech said he would not vote for his successor after being forced from office by the “party I founded”.

“I cannot vote for those who tormented me,” he said.

An opinion poll last week saw the MDC close the gap with the ruling Zanu-PF party from 11 percentage points to three, with 20 per cent of voters undecided.

President Mnangagwa urged the country to remain peaceful during the historic election, tweeting: “Let us vote with peace in our hearts. We are one people, with one dream and one destiny. We will sink or swim together.”

The election is regarded by many as a potentially pivotal moment for the long-suffering African nation. It could either bring international legitimacy and investment or signal more stagnation if the vote is seriously flawed.