Tendai Biti, a senior member of the MDC Alliance (Zimbabwe opposition), was arrested at the border with Zambia, according to his lawyer.
Police had issued an arrest warrant against Mr. Biti, accusing him of “illegally” announcing that his party leader, Nelson Chamisa, had won the presidential election last Monday.
He is also accused of inciting violence when supporters of the MDC Alliance clashed with security forces two days later, killing six people.
His lawyer, Nqobizitha Mlilo, told the AFP news agency that Biti was going to Zambia to seek asylum.
The Zimbabwean state broadcaster said in the news that Tendai Biti had been arrested is a fake news, while the police say they have no information about any arrest of the opposition leader.
Mr. Biti was the finance minister in a unity government that was formed following disputed elections in 2008 and helped stabilize the economy after years of hyperinflation.
The election was won by President Emmerson Mnangagwa, but the opposition says the result has been rigged.