Zimbabwe Lawyers for Human Rights spokesperson Kumbirai Mafunda said Shoko was arrested on Wednesday.
“They detained him at Harare central police station where they charged him with criminal nuisance,” Mafunda told AFP.
“They said his statements were likely to interfere with the ordinary comfort, peace and quiet of the public.”
Police not immediately available to comment.
Mafunda said Shoko, who heads the pressure group Children of Zimbabwe War Veterans Association, was also charged with public violence for allegedly taking part in protests by opposition supporters after July 30 elections.
At least six people were killed after soldiers opened fire at the protests.
Mngangagwa won the presidential election, though the results are being challenged in court.
The government and security forces have been accused of a violent crackdown on MDC opposition supporters since the vote.
Mnangagwa succeeded long-time ruler Robert Mugabe who was ousted in November 2017 following a brief military takeover.