The meeting comes at a time when Zimbabwean society has been battered by a combination of economic crises and political conflicts, marked by severe shortages of food and fuel and by strikes that have temporarily shut down most major businesses and industries.
In South Africa and other nations, outrage has mounted over reports of systematic human rights violations by the government, including the arrest and torture of hundreds of opposition supporters in March.
Bheki Khumalo, a spokesman for President Thabo Mbeki of South Africa, confirmed that Mr. Mbeki would go to Zimbabwe, along with President Olusegun Obasanjo of Nigeria and President Bakili Muluzi of Malawi, who is chairman of a South African task force on Zimbabwe.
Responding to news reports that the three leaders planned to urge Mr. Mugabe to step aside and allow the establishment of a transition government, Mr. Khumalo said: "The issue of when and whether President Mugabe retires is a matter for President Mugabe to decide. What we can do is go there, hear what is happening and see what can be done to get the parties back to negotiations. It is clear that they have to work together."
Still, hopes are high among Mr. Mugabe's opponents that the one-day visit will start a process of political and economic change. It will be the first visit by Mr. Mbeki and Mr. Obasanjo, two of the continent's most influential heads of state, in more than 18 months. For Mr. Mbeki, the crisis in Zimbabwe has evolved from a top foreign policy priority into one of his most vexing domestic quandaries.
Mr. Mbeki has offered support to Mr. Mugabe's government, publicly playing down reports of official abuse in Zimbabwe and saying his government prefers to pursue a policy of "quiet diplomacy."
Once a model of progress and prosperity in a region ravaged by war and famine, the country has fallen into turmoil. Unemployment is above 60 percent. Inflation has reached record levels. Industries struggle against rolling blackouts and fuel shortages. Meanwhile, sharp declines in agricultural production have left most of the country's 11.6 million people in need of assistance.
Mr. Mugabe, 79, has governed Zimbabwe since the end of white-minority rule in 1980. He won elections last year in a contest that was dogged by charges of vote-rigging and violence. Several Western governments and human rights groups have accused him of using fraud and repression to retain his power.
On Friday, Amnesty International issued a report charging Mr. Mugabe with enacting measures that gave legal cover to abuses of the press and other independent groups.
"The Zimbabwean authorities, particularly the police, are using repressive legislation to systematically harass, arrest and torture with impunity those perceived to be supporting political opposition and exposing human rights violations," the organization said.
Talks between the leading opposition group, the Movement for Democratic Change, and the Mugabe government ended last year when the group challenged the legitimacy of the Mugabe government in court. The government countered by charging the group's president, Morgan Tsvangirai, with treason.
In recent weeks there seems to have been a cautious but notable thawing on both sides. Mr. Mugabe indicated in a rare television interview his willingness to meet with opposition leaders if they dropped their lawsuit.
In a statement last week the opposition group indicated a willingness to begin "serious and sincere" negotiations with the governing Zimbabwe African National Union Patriotic Front, if the government agreed to disband militias that have been charged with systematic harassment, imprisonment and torture of government opponents. [End]