Fifteen members of the MDC formation led by Zimbabwean Industry Minister Welshman Ncube, who were arrested in Tsholotsho district Monday while canvassing for support, where released late Tuesday without charge.
The activists, among them councilors Abel Dube, Petros Mahonondo and Rhoda Ncube; secretary for Matabeleland North Robert Mgezelwa Ndlovu and provincial spokesman Minutewell Ncube, were ordered to report back May 30.
The MDC said in a statement Monday that its members faced charges of holding meetings without police authorization under the draconian Public Order and Security Act.
But it denied the accusations saying its members were on a door-to-door campaign, and never held any public gatherings.
Spokesman Nhlanhla Dube told VOA the release of the activists without charge was proof that their detention was illegal and baseless.
"Upon release, the police said they should report at the Tsholotsho Police Station on May 30 to give statements regarding their arrests," Dube said.
"We find that very odd, if not absurd because the reality is that the first thing that the police do when someone is going to be charged, is that a statement is taken."
Zimbabwean police are accused of abusing POSA to target the MDC and civil society groups critical of President Robert Mugabe's ZANU-PF party, whose members are rarely subjected under the law.
Efforts by MDC parliamentarians to amend the legislation have faced stiff resistance in the ZANU-PF-dominated Senate.
Elsewhere, the trial of outspoken National Healing co-Minister Moses Mzila Ndlovu, Member of Parliament for Bulilima West, started in a Hwange court Monday.
Mzila is accused of inciting the public to revolt against the government. He denies the charge.
The trial was postponed to May 8.