Madhuku was referring to the independence war veterans that the opposition said Mugabe had sent out to ensure a second round victory.
"You will get the war veterans again on the war path. If there is a runoff the war veterans would make it difficult for some people to turn out to vote," said Madhuku, a critic of Mugabe and chairman of pressure group, the National Constitutional Assembly.
The opposition has also called for a general strike to be launched from Tuesday, the day after a court is due to rule on its bid to force the publication of the election result.
The political turmoil has added insult to injury for a nation which is deeply trapped in an economic crisis.
With inflation raging at higher and prices soaring irrationally, the government introduced earlier this month a 50-million-dollar Zimbabwe note, which could only buy three loaves of bread then and is depreciating quickly.
The International Monetary Fund said Saturday that even before the disputed March 29 election, things were bad in Zimbabwe.
It added that independent finance houses calculated inflation at around 290,000 percent in Zimbabwe compared to the official figure of 100,500 percent.
If not properly handled, the crisis in Zimbabwe has the risk of escalating toward the style of the deadly riots in Kenya, which was once one of Africa's most stable countries. The recent clashes in Kenya left more than 1,000 people killed and 350,000 others displaced.
(Xinhua News Agency April 14, 2008)
