Tsvangirai's Movement for Democratic Change party voiced skepticism about the agreement on Tuesday, but he told South African newspaper The Star "Everyone agrees that, subject to the clearing of all the issues that are outstanding, a coalition government can be formed."
Tsvangirai said negotiators would meet in Harare on Thursday to try to resolve those issues, including distribution of cabinet posts and the control of security agencies.
Tsvangirai's comments contradicted more negative assessments from other members of his party, feeding reports of a rift in the MDC.
"There seem to be internal struggles in the MDC which presents Tsvangirai with a challenge, though it's likely he will prevail over the hawks in his party," Eldred Masunungure, a politics professor at the University of Zimbabwe, said in a telephone interview with Bloomberg News.
President Robert Mugabe and Tsvangirai agreed to share power last September after Tsvangirai won the presidential election, but not by a wide enough margin to prevent a run-off. After reports of political violence prevented the second round of voting, the parties agreed to share power, but the parties have continued to disagree on how to allocate key government jobs and powers.
The political crisis has contributed to the breakdown of water, sanitation and health systems, allowing conditions for the bacterial illness cholera, which spreads through contaminated water. The World Health Organization announced Wednesday that the death toll for the cholera outbreak that began in August has now passed 3,000.
More than 1,000 of those deaths occurred in the past two weeks, the BBC reported.
In early December, Mugabe's government declared the cholera epidemic a national emergency, allowing groups such as Oxfam, Doctors Without Borders, the WHO and USAID to provide aid, but the efforts have not been able to keep up with the spread of the disease.
One of the South African mediators at the power-sharing summit, top presidential aid Frank Chikane, urged the parties to push forward in forming the government to tackle the cholera outbreak and the humanitarian issues facing Zimbabwe's population.
"The key thing is that the leadership must go back to their constituencies and report back and say this is what has come out of that process and for the sake of the people of Zimbabwe let us agree, form the government, because we can solve most problems when we are in government," said Chikane, the Agence France-Presse reported.