"A full investigation into the circumstances of the tragic accident is both necessary and fundamental," said the party in a statement.
Tsvangirai’s wife, Susan, was killed in the car crash on Friday near Harare, while he was injured and admitted to hospital.
The couple were headed to their hometown of Buhera where Tsvangirai was to hold a rally, when their car was hit by a truck.
SACP spokesperson Malesela Maleka said Susan Tsvangirai’s death was a great loss.
"Like all mothers, Mrs Tsvangarai was the greatest pillar of strength and support to her husband, more so in the last decade of political upheaval she described as "an endurance test".
Maleka said the party also wished the prime minister a speedy recovery. – SAPA