Police in Zimbabwe have arrested the head of the main trade union, the ZCTU, ahead of a planned protest over the country's deepening economic problems.

ZCTU President Peter Mutasa was among several dozen people detained in various cities across Zimbabwe.

Police had refused to give permission for a planned demonstration in the capital, Harare, saying it would not be safe because of an outbreak of cholera.

Zimbabwe has suffered shortages of fuel and some basic foodstuffs since the government announced a new tax on electronic payments last week.

A foreign currency shortage has worsened since President Emmerson Mnanagagwa won a disputed election in July.