Zimbabwe’s leading opposition candidate accused the country’s electoral authorities of trying to suppress voter turnout at presidential elections on Monday, raising fears of a disputed outcome to the historic poll.

Millions of Zimbabweans turned out to vote in the country’s first presidential, parliamentary, and local government elections since dictator Robert Mugabe was ousted in a military coup in November.

The outcome will decide whether Emmerson Mnangagwa, a 75-year-old former ally of Mr Mugabe, or Nelson Chamisa, a 40-year-old lawyer and preacher leading the opposition MDC alliance, will be the country's next president.

The only poll released in the run up to the vote showed Mr Mnangagwa leading Mr Chamisa by just 3 per cent, and the results, which must be announced by Saturday, are expected to be tight.