Blantyre - Malawi's former president Bakili Muluzi, who was detained in 2008 for plotting to topple his successor, is suing the state for false arrest, according to court documents seen by AFP on Tuesday.
Muluzi, who led the southern African nation between 1994 and 2004, was arrested in May 2008 at the country's main airport as he returned from a holiday in Britain.
He and eight others, including top former army and police chiefs, were accused of trying to overthrow then president Bingu wa Mutharika and charged with treason and conspiracy to murder.
The group was never prosecuted and some have successfully sued the state.
Muluzi has repeatedly dismissed the allegation of a plan to topple Mutharika, his hand-picked successor.
"The state does not have sufficient grounds to support its treason charges against him," said one of Muluzi's lawyers, who are claiming compensation.
"There is a need to compensate Muluzi," said Kalekeni Kaphale, adding that the arrest "caused untold loss of confidence in him by the people who otherwise trusted him."
Muluzi wrested power from dictator Kamuzu Banda in the country's first democratic elections, and is credited with introducing democratic and human rights reforms.
His image has been tainted by long-standing corruption charges, including the accusation that he stole $12m in aid money.
He is the most senior figure to face corruption charges in a sweeping anti-graft campaign launched by Mutharika in 2004.