"Those are the issues, that's the sole agenda. There is no substantive agenda," Mlilo told AFP.
South African President Thabo Mbeki is the region's long-time mediator between the opposition and Zimbabwean President Robert Mugabe's ruling party.
South African government officials -- though not Mbeki himself -- were involved in Thursday's discussions at an undisclosed location in the capital Pretoria, said presidential spokesman Mukoni Ratshitanga.
Zanu-PF was represented by Patrick Chinamasa, the Justice minister and Nicholas Goche, the Labour minister and the MDC by Tendai Biti, its secretary-general and Elton Mangoma, its deputy treasurer-general.
The talks came as the UN Security Council prepared to discuss possible sanctions against Zimbabwe over the presidential run-off which was marred by allegations of violence and vote-rigging.
A draft resolution authored by the US calls for a freeze on assets and a travel ban for Mugabe and 13 close associates, as well as an arms embargo.
It would also demand that the Harare government "begin without delay a substantive dialogue between the parties with the aim of arriving at a peaceful solution that reflects the will of the Zimbabwean people as expressed by the March 29 [first-round presidential] elections."
Tsvangirai finished ahead of Mugabe in that election but did not gain the outright majority needed to avoid a run-off. He pulled out of the June 27 poll just days before it took place and Robert Mugabe, Zimbabwe's leader for 28 years, claimed victory.
G8 leaders meeting in Japan this week called for a special envoy to assist in mediation efforts while rejecting the legitimacy of Mugabe's government and threatening further sanctions against his regime.
A number of African governments, including South Africa, have rejected the push for further sanctions, saying it will only worsen the situation.