The two signed a deal on Monday, with Mugabe relinquishing some powers for the first time in nearly three decades of rule under pressure from regional leaders and a growing economic crisis.
But there has been little progress since.
Deal 'a humiliation'
"The meeting was inconclusive, it was a deadlock and has been referred to the negotiating teams for further work to try and find common ground," said Nelson Chamisa, an MDC spokesman.
The state-run Herald newspaper said earlier that Mugabe had told a meeting of his Zanu-PF party that the agreement was "a humiliation".
In an address broadcast live on television, Mugabe assured Zanu-PF that it remained in "the driving seat" and "will not tolerate any nonsense from our new partners".
Under the power-sharing agreement, a new cabinet is expected to see 13 cabinet posts controlled by Tsvangirai's party, with a breakaway MDC faction likely to control an additional three ministries.
Mugabe's Zanu-PF, which lost control of parliament in the March election for the first time in 28 years, is likely to have 15 ministers in the cabinet.
The agreement - which involved Mugabe, Tsvangirai and Arthur Mutambara, who heads the breakaway faction of the MDC - followed weeks of tense negotiations to end a political crisis in Zimbabwe compounded by the veteran leader's disputed and unopposed re-election in a widely condemned vote in June.
Under the agreement, Tsvangirai will become prime minister and chair a council of ministers supervising the cabinet.
"People are saying Mugabe is coming under a lot of pressure from people within Zanu-PF who are not happy about the deal and that Morgan Tsvangirai was made prime minister," Mutasa reported.
Patrick Chinamasa, the justice minister, said Mugabe and Tsvangirai had shifted talks over the cabinet to their negotiators after finding the task "labourious".
Zimbabweans are hoping the signed agreement, brokered by Thabo Mbeki, the South African president, will be a first step in helping to rescue the once prosperous Zimbabwe from its economic crisis.