Tsvangirai is in Johannesburg, in neighbouring South Africa, from where he took part in the MDC meeting via a video link-up.
The MDC leader will make a formal announcement on his attentions on Monday, George Sibotshiwe, a party spokesman, said.
Al Jazeera's Haru Mutasa, reporting from Harare, said that the MDC's delay was causing more uncertainty in the country.
"People are struggling to make ends meet ... They are in limbo and they want to hear from their leaders what the way forward is - and right now there is no answer," she said.
"People are frustrated and confused. Their biggest fear is that as long as this deadlock continues there is going to be more intimidation in some parts of the country."
The long-delayed election results, released on Friday, showed Tsvangirai had received 47.9 per cent of the vote, beating Mugabe's 43.2 per cent.
But under Zimbabwe election rules a candidate needs to poll 50 per cent to avoid a second round of voting.
Mugabe accepted the results and quickly confirmed that he would take part in the run-off.
The MDC previously rejected the idea of a run-off and on Friday accused the electoral commission of inflating Mugabe's number of votes by 47,000 and deflating those for Tsvangirai by 50,000.
If the MDC refuses to take part in a second round, Mugabe would keep his hold on power, according to electoral law.
Tsvangirai has been lobbying regional powers to pressure Mugabe to step down.
Western powers have cast doubt on the validity of Zimbabwe's election results and on whether the country can hold a fair run-off vote.
In Washington, a US state department spokesman said that the recently announced results had "rather serious credibility problems".
|The MDC has said some of its supporters have|
been attacked by Zanu-PF activists [AFP]
International rights and aid groups have also expressed alarm over political violence following last month's election.
The MDC has claimed some of their supporters have been subject to attacks from Zanu-PF activists.
There have also been reports of thousands of Zimbabweans fleeing the country for fear of violence.
US-based Human Rights Watch called the chances of a free and fair election a "tragic joke", following alleged attacks on opposition supporters by the army and other groups allied to the Zanu-PF.
But Bright Matonga, Zimbabwe's deputy minister of information, rejected the claims, telling Al Jazeera that "Zimbabwe is capable of running a very free and fair election".
He blamed the British government for attempting to undermine the elections.
"The last election was free and fair. The only violence that came up was the violence that was instituted by the British government - they paid some youths and gave them drugs."
He said it was "part of the British strategy to cause as much chaos and violence as possible ... so that they can justify the idea of forming a government of national unity".