TOKYO, Oct. 20 -- A Japanese journalist could be facing a prison term of up to 18-months under charges of defaming South Korean President Park Geun-hye, local media reported Tuesday.

South Korean prosecutors presented their case for the custodial sentence for Tatsuya Kato, a 49-year-old former Seoul bureau chief for the Sankei Shimbun newspaper, claiming that he knowingly published defamatory rumors about the president and a former aide Jeong Yun-hoe.

At a hearing held at the Seoul Central District Court at which Kato was present, the prosecutors demanded an 18-month prison term be handed down for Kato writing an article based on local press rumors suggesting that Park was absent for several hours with a male aide who was married at the time, when the Sewol ferry sank in April last year, killing more than 300 passengers, many of whom were young school children.

The Sewol ferry incident has been a sore point for the South Korean government who drew a lot of flak for what has been described as bungled rescue attempts in the hours following the ferry sinking -- a globally watched tragedy and the worst maritime disaster in South Korea's history.

Kato's suggestions of Park's impropriety during a national disaster added fuel to the fire, with the accusations underscoring a belief that the South Korean government could've reacted more efficiently in dealing with the ferry disaster.

While prosecutors have argued that along with defaming Park, Kato's story also damaged the honor of the victims of the disaster, Kato's lawyers have maintained that his article was not defamatory, and following the rumors about Park subsequently being proved to be false, Kato published a note saying he had no intentions of contesting this point.

Kato was indicted for alleged defamation of the president in August of last year after he raised suspicions that Park may have been with Jeong on the day of the Sewol ferry disaster and that the two had an intimate relationship.

The Japanese government has said the prosecution's demand for an 18-month jail sentence was "extremely unfortunate," with Chief Cabinet Secretary Yoshihide Suga, Japan's top government spokesperson, telling a press briefing Monday that the government here has expressed its concerns over press freedom to its South Korean counterparts and called for an "appropriate response" regarding Kato's case.

The Sankei Shimbun, for its part, has said in a statement that it is surprised and angered by the prosecutor's push for a custodial sentence and has urged the Seoul Central District Court to base its final judgement on international standards and the "basics of democracy."

The Sankei Shimbun, however, is no stranger to controversy, and is believed in South Korea to harbor anti-Korean sentiments -- more so following Kato's article based on local unsubstantiated rumors.

Adding to the newspaper's checkered history, in late 2014 the newspaper ran an advertisement promoting an anti-Semitic book and, furthermore, one of its regular writers, Ayako Sono, wrote an article suggesting that while Japan accepting more immigrants may be a solution to bolster its shrinking workforce, the government should adopt a former South African apartheid-like law to segregate non-Japanese from Japanese.

Kato was indicted in October last year without arrest, with the trial starting a month later. The sentencing is slated for Nov. 26, sources close to the matter said Tuesday. Enditem