The vote on July 30 is “on path to be determined as a fraud election,” he said, adding that the Zimbabwe Election Commission was “biased and has lost the confidence of the people of Zimbabwe.”
He said that his party would not boycott the vote as it would still win against President Emmerson Mnangagwa and ruling ZANU-PF party.
It is the country’s first election since Robert Mugabe was ousted in November.
“We can’t boycott our mandate, winners don’t boycott. Victory is inevitable,” Chamisa told reporters.
“Mnangagwa knows defeat is staring in his face… We are going to turn out in our numbers (to vote) and defeat them.”
Elections during Mugabe’s 37-year reign were regularly marred by fraud and violence, but Mnangagwa has vowed to hold a peaceful and fair vote.
Mnangagwa, a ZANU-PF loyalist and former ally of Mugabe, has invited international observers — including previously-banned European Union and Commonwealth teams — to assess the polls.
Chamisa, 40, took over leadership of the MDC after a bitter succession battle followed the death of veteran party leader Morgan Tsvangirai in February.
– The post-Mugabe era –
In 2008, Tsvangirai pulled out of the presidential run-off vote after attacks orchestrated by the state and ZANU-PF claimed the lives of at least 200 of his supporters.
Monday’s election comes after Mugabe, now 94, was forced to resign following a brief military takeover in November that ended his 37 years in power.
Mnangagwa’s critics say that he relies on the support of the military and that the same corrupt elite from Mugabe’s era still have their grip on power.
Both candidates have campaigned on a pledge to revive the economy, which was shattered under Mugabe’s autocratic rule as the seizure of white-owned farms wrecked the agriculture sector and triggered hyperinflation and economic collapse.
Previously solid health and education services collapsed, millions fled abroad to seek work and poverty rates are still climbing.
The United Nations on Tuesday warned of growing concern over alleged intimidation and threats of violence in the runup to the historic election.
“We call on the authorities — and political parties and their supporters — to ensure that the elections are not marred by such acts,” the UN High Commissioner for Human Rights (UNHCR) said in a statement. DM