Zimbabwean police beat dozens of opposition supporters and arrested several outside a court in the capital Harare on Thursday, after Citizens Coalition for Change (CCC) party members were denied bail following their arrests two weeks ago.

A Harare magistrate denied bail to the party's interim leader Jameson Timba and 78 activists arrested on June 16 for holding a political gathering which authorities said was unauthorised.

Timba took over as interim leader of the CCC after former leader Nelson Chamisa quit the party in January, alleging it had been hijacked by the ruling ZANU-PF party.

Police anti-riot units guarded the entrance to the court and the arrests were made hours after President Emmerson Mnangagwa said those who were believed to be causing trouble would "be dealt with".

A Reuters reporter saw the arrest of one woman holding a placard demanding the release of the activists, while some were bundled into police trucks and others fled baton-wielding police.

The activists were denied bail on concerns they would cause public disturbances and interfere with witnesses in the state's case, their lawyer Agency Gumbo told reporters outside court after the online bail hearing.

Gumbo said that his team would appeal the decision in the high court.

"We don't believe there are any compelling reasons to deny the accused persons bail."