Zimbabweans queued to vote yesterday in the most crucial election since independence in 1980, many of them desperate to end the misery of economic collapse under veteran President Robert Mugabe.
But the opposition said Mugabe's ruling ZANU-PF party was planning to steal victory through multiple voting by its supporters.
It said voting ink could be removed from ballots with detergent.
Combined with a bloated voter role and the printing of three million extra ballot papers this "ensures that there will be multiple voting" said Tendai Biti a senior official in the MDC party of main challenger Morgan Tsvangirai.
"There is absolutely no doubt we have won this election," he added.
Zimbabwe, its once prosperous economy in ruins, is suffering the world's highest inflation rate at more than 100,000 per cent, chronic shortages of food and fuel and a rampant HIV/AIDS epidemic that has contributed to a steep decline in life expectancy.
Mugabe, who blames the collapse on Western sanctions, faces the biggest challenge of his 28-year rule from veteran rival Tsvangirai and ruling ZANU-PF party defector Simba Makoni. Many voters told Reuters they wanted a new government.
"I am voting for change. I am praying for a free and fair election. It is the only way this country can move forward," said Richard Mutedzi, 25, a trained mechanic who voted in Chitungwiza, 30 km south of Harare.
He said he was forced to sell odds and ends because of lack of work.
Despite the odds stacked against Mugabe, 84, many analysts believe he will be declared the victor.
Mugabe oozed his usual confidence when he voted in Harare yesterday. "We will succeed. We will conquer," he said, denying that he planned to steal the vote. "Why should I cheat? The people are there supporting us. The moment the people stop supporting you, then that's the moment you should quit politics," he said.
The opposition fears many supporters will not have time to vote, saying polling stations have been distributed in favour of Mugabe's rural strongholds.
Biti, secretary-general of Tsvangirai's MDC faction, said voting was slow and some election agents were prevented from entering polling stations.