The rallies were supposed to be the opposition leader's first public appearance following his release from prison last month, along with dozens of his supporters, where he was detained for organising protests in January against the result of last year's presidential election.

Mr Kamto's release was meant as a gesture of national reconciliation as President Paul Biya, in power for 37 years, tries to quell a separatist revolt.

The first of the two rallies was scheduled for Saturday at the Omnisport stadium in Yaoundé. But the city's police have banned it, privately owned news site Journal du Cameroun reports, urging Mr Kamto's Cameroon Renaissance Movement (CRM) party to first seek authorisation from the minister of sport and the stadium's management.

A second rally, planned for 9 November in Douala, has also not been given the go-ahead, the authorities in the city are reported as saying .