Southern African leaders are set to start a two-day summit in Johannesburg, with hopes that stalled talks on Zimbabwe's power-sharing may resume, BBC reported.
The Sadc gathering will be chaired by South African President Thabo Mbeki, who has been mediating in the talks.
Both Zimbabwean President Robert Mugabe and opposition leader Morgan Tsvangirai are planning to attend the summit.
But Botswana's President Seretse Khama Ian Khama has refused to attend because of Mr Mugabe's presence.
Botswana's government said he did not want the Southern African Development Community (Sadc) to give legitimacy to the widely condemned second round of Zimbabwe's presidential election in June, in which Mr Mugabe was the only candidate.