A Zimbabwean activist, Sten Zvorwadza, was arrested after referring to President Robert Mugabe, a 93-year-old “living dead”.
Lawyers said Wednesday that the arrest was the latest case of dissent.
Zvorwadza, the head of a street vendors’ union, was accused of defaming the president in an interview, where he also alleged that Mugabe was “old” and “dreamy”.
Mr. Zvorwadza is a prominent anti-Mugabe activist who led several demonstrations in which he always asked the veteran leader to resign.
The worsening economic crisis in Zimbabwe has pushed many people into the informal sector.
Zvorwadza is expected to appear in court, the Zimbabwe Human Rights Lawyers Group (ZLHR) said.
Authorities have often suppressed criticism of President Mugabe, who has ruled since 1980.
In March, two journalists were arrested for a report in which they revealed that the president who goes abroad for regular medical treatment was in “poor health”.
A pastor was also arrested after prophesying that President Mugabe was going to die on 17 October this year.
Last week, police arrested another journalist who reported that President Mugabe’s wife, Grace, had given second-hand underwear to supporters.
Despite his advanced age and his shaky health, the ruling Zanu-PF party has designated Mugabe as his candidate for the 2018 presidential election.