Speaking on a trip to France, Tsvangirai said Mugabe had to keep a promise to form a coalition with the opposition Movement for Democratic Change after disputed elections otherwise his legacy as a liberation hero would be ruined.
"If he wants to proceed with a government without us I know he knows that is unrealistic and that government will not be functional," Tsvangirai said.
"He needs us, we control parliament and he needs a deal for his own sake, to salvage his own legacy."
Although Mugabe and Tsvangirai both signed an agreement in mid-September to share power after a protracted post-election dispute, its implementation has stalled amid a row over the division of key ministries.
Although Mugabe’s camp has warned the veteran president now plans to form a government "forthwith" and berated the MDC for trying to "dictate from the sidelines".
However, the MDC wrested control of parliament from ZANU-PF for the first time in March’s joint presidential and legislative elections and Mugabe is dependent on parliament to pass the annual budget.
Western nations have said they are ready to release hundreds of millions of dollars in aid, but not while Mugabe retains his sole grip on power.
After meeting with lawmakers, Tsvangirai said Europe must "put as much pressure as they can to ensure that President Mugabe and ourselves … come to a conclusion on this political impasse."
Turning to the extreme poverty in which most Zimbabweans live and which many blame on Mugabe’s economic policies, Tsvangirai said his people were "facing a dire humanitiarian situation."
"By January we will be feeding five and a half million people, that’s three quarters of the population," the oppostion leader told reporters, adding thet he had urged EU leaders to make humanitarian aid their top priority.
He made the appeal the same day that the medical charity Doctors Without Borders reported that up to 1.4 million people were at risk of cholera if it continues to spread unchecked across Zimbabwe.
The European Commission provided Zimbabwe with around 90 million euros (114 million dollars) in humanitarian aid in 2007, but all development aid to Mugabe’s regime has been frozen.
With inflation running at more than 231 million percent, half the population requires emergency food aid, while a breakdown in basic services has led to deadly outbreaks of cholera in Harare.