"There are literally hundreds of people that have been beaten up, that have been stoned by ZANU-PF supporters. They have suffered bruises, tissue injuries, various degrees of injuries", he said.
He said police had failed to protect the MDC.
"They watched us as these ZANU-PF youths destroyed our property and assaulted our members," he said.
Biti, who is also Zimbabwe's finance minister in the power-sharing government between Mugabe and Tsvangirai, accused ZANU-PF of using violence to provoke fear in the run-up to elections expected to be held as soon as next year.
"It is self-evident that ZANU-PF is already building up to the next election. It is quite clear that we are in a chaos scenario where they are unleashing violence," he said.
Police spokesman Oliver Mandipaka said he had received reports of clashes but was still gathering information and could not comment or give details.
ZANU-PF national spokesman Rugare Gumbo said he had not heard about the incident.
"But we are not surprised by the claim that ZANU-PF is the one that caused the violence. That is what we always know the MDC will say," he said.
Zimbabwe's unity government has been riven by problems since it was formed in February 2009, after a bitterly disputed first-round 2008 vote where neither candidate won an absolute majority.
That election sparked a wave of attacks that killed more than 200 MDC supporters. To end the bloodshed, Tsvangirai pulled out of the second round against Mugabe, the country's ruler since 1980.
The power-sharing pact was meant to introduce security sector reforms that would prevent a repeat of the violence but Tsvangirai has accused Mugabe of failing to uphold his end of the deal.
Tsvangirai briefly quit the coalition in late 2009 but regional mediators persuaded him to resume working with Mugabe.
The leaders are supposed to oversee the drafting of a new constitution that will steer the country to fresh elections but the process has been marred by violent disruptions of community meetings by Mugabe supporters and is running more than a year behind schedule.
- AFP, AAP