Malawian politician Gwanda Chakuamba has been arrested following his sacking last week as a cabinet minister.
Chakuamba served a decade in jail for sedition under Banda
He has been detained for questioning over a speech at the weekend in which he predicted that the president would be out of office by Christmas.
His party's MPs planned to join the opposition to impeach President Bingu wa Mutharika, he had warned.
He was one of the main opposition candidates in last year's elections but joined a reconciliation government.
The veteran politician was dismissed as agriculture minister and replaced by the transport deputy minister, Sidiq Mia last week.
He has served more than a decade in jail for sedition under the late Malawian leader, Hastings Banda.
Viva Nyimba, Mr Chakuamba's lawyer, said the charge was for a misdemeanour which he said carries a fine of up to $15.
He described the arrest as political persecution because his client has been denied police bail for what he called "a minor offence".