Taiwanese prosecutors have charged former president Ma Ying-jeou with leaking secret information obtained from wiretapping a political opponent.
Mr Ma has insisted he did not break any laws as he was merely fulfilling his duty as head of state.
If found guilty, he may be jailed for up to three years for each charge.
The criminal charges are in addition to a separate legal case relating to the same matter in 2013.
Mr Ma's eight-year presidency ended in 2016, when his Kuomintang party lost to the Democratic Progressive Party (DPP) in last year's general election.Image copyright AFP/Getty Images Image caption Anti-Ma protesters have called for him to be detained as a "first step to reform"
Prosecutors say that Mr Ma ordered that the contents of secretly-recorded phone calls between DPP lawmaker Ker Chien-ming and the parliamentary Speaker be given to other officials.
They said that by giving this order, Mr Ma broke laws on the protection of personal information, release of secrets, and communications security and surveillance.
Mr Ma has argued that he was merely carrying out his responsibilities as president, as the content of those phone calls related to alleged influence-peddling by Mr Ker and the Speaker.
Mr Ma has already appeared in court several times in recent months for a separate lawsuit brought by Mr Ker over the same matter. That case's verdict is set to be announced later this month
His supporters say he is a victim of political score-settling.