Thabo Mbeki, the South African president, was appointed by the Southern African Development Community in March this year to bring Zanu-PF and the MDC to the negotiating table.
"I can only confirm that we have representatives in South Africa attending roundtable discussions with the country's other political players," Nelson Chamisa, spokesman for the opposition MDC, said.
"In the interest of diplomacy, I am under instructions not to comment or give any more detail until such a time when both parties have agreed to make a statement."
Zanu-PF was represented at the meeting by Patrick Chinamasa, justice minister, and Nicholas Goche, labour and social welfare minister.
Tendai Biti and Welshman Ncube were sent from the two factions of the divided opposition, with South African local government minister Sydney Mufumadi as chairman.
An opposition source told the AFP news agency that the meeting was to pave the way for future discussions to resolve Zimbabwe's political and economic crisis.
"The meeting is discuss the content, process and the logistics of the talks between us and Zanu-PF to try and resolve the national crisis," he said.
Zimbabwe is gripped by an economic and politcal crisis. Inflation is 3,714 per cent and rising; power and water cuts occur daily and food, hard currency, gasoline, medicines and other essential goods are in short supply.
The UN said last week that four million of the country's population of 12 million will be dependent on food aid by the end of the year because of the combined effect of a drought which and the collapse of the farming system.