Movement for Democratic Change spokesman Nelson Chamisa said Tsvangirai was taken to hospital but was not in a critical condition. He was still awaiting details.
Another MDC source said Tsvangirai’s wife, Susan, was killed.
Tsvangirai was sworn in last month as prime minister of a government with old rival President Robert Mugabe, set up to try to end a political and economic crisis that has brought the once relatively prosperous country to ruin.
MDC sources said Tsvangirai’s motorcade was involved in the accident some 50 km (30 miles) south of Harare as he headed to his rural home in Buhera.
Tsvangirai, who turns 57 on Tuesday, has been married to Susan for 31 years. They have six children.
Although Susan was not actively involved in Tsvangirai’s party, she has supported him and appeared at campaign rallies with her husband over the last 10 years.
The new government faces an array of problems: food and fuel shortages, the world’s most serious hyperinflation and a cholera outbreak in which nearly 88,000 people have been infected, with nearly 4,000 killed, according to the World Health Organisation.
Tsvangirai is under pressure to rescue the ruined economy. Analysts say he may also face new political challenges from Mugabe, pushing to give his ZANU-PF party an upper hand over the MDC in the new administration.
Tensions have been rising in the new government over the arrest of MDC official Roy Bennett.
Zimbabwean police have arrested a magistrate who tried to release Bennett while his case was still before the country’s highest court, a police spokesman said Friday.
Zimbabwe’s Supreme Court Thursday granted prosecutors the right to appeal against a ruling by a High Court judge to grant bail to Bennett, a former white farmer.
The International Monetary Fund and World Bank are expected in Zimbabwe next week to review the country’s economic situation and discuss policies to address the humanitarian crisis.
South Africa is considering opening a credit line to help neighbour Zimbabwe rebuild its shattered economy after years of political and economic crisis, the Financial Mail reported on Friday.