TAIPEI (BLOOMBERG) - Ex-Taiwanese President Ma Ying-jeou was sentenced to four months in jail for leaking details of a criminal investigation while still in office, although the former Kuomintang leader could still avoid jail time by paying a fine or winning on appeal.

Taiwan's High Court on Tuesday found Ma, 67, guilty of violating the Communication Security and Surveillance Act, according to high court division chief judge Lin Ruey-bin.

Ma had been found not guilty of the charges by a Taipei district court last year, a verdict prosecutors appealed. Ma said he would appeal Tuesday's (May 15) decision in a statement released by his office after the verdict.

Ma could also avoid time in jail by paying a NT$120,000 (S$5,365.80) fine, pending approval from prosecutors.

The judge found that Ma had improperly disclosed a wiretapped June 2013 conversation between the former legislative speaker, Mr Wang Jin-pyng, and a Democratic Progressive Party lawmaker who had recently been acquitted of breach-of-trust allegations.

Ma accused Mr Wang of pressuring prosecutors not to appeal against the acquittal of the lawmaker, Mr Ker Chien-ming.

While Mr Wang was never indicted for wrongdoing, Mr Ker sought charges against Ma for the leak.

The former president was found to have broken the law by discussing details of the call with the then-premier and his deputy secretary general, according to the court.

Ma, who governed from 2008 to 2016 and championed closer ties with China, became Taiwan's third consecutive president to face criminal charges after leaving office.

His predecessor, Mr Chen Shui-bian, of the rival Democratic Progressive Party, was granted medical parole in 2015 while serving a 20-year prison sentence following his corruption conviction.

Mr Lee Teng-hui, who oversaw Taiwan's transition to direct democracy as president from 1988 to 2000, was found not guilty of money laundering and embezzling government funds in November 2013.