South Korea's opposition parties on Friday vowed to revise the existing law on honoring the symbolic May 18 movement, adding that any attempt to defame its spirit should be punished.

The move, if made into law, would make it illegal to use newspapers, TV broadcasts or any other form of publication to distort or defame the democracy movement. Those found guilty of breaking the rules could face fines of under 50 million won ($44,000) and a jail term of less than five years.

On May 18, 1980, more than 200,000 citizens of Gwangju, 329 kilometers south of Seoul, rose up against the military junta led by Gen. Chun Doo-hwan, who took power following the turmoil left by the assassination of then-President Park Chung-hee the previous year. The late president had ruled the country for 18 years before his death and is the father of incumbent President Park Geun-hye, while Chun went on to become a president of South Korea.

The uprising is viewed as one of the key turning points in South Korean history that eventually led to the country shedding its authoritarian past.

"Although 36 years have passed since the movement, there are still attempts to distort and defame the historical event," said Rep. Kim Chong-in, the interim leader of the main opposition Minjoo Party of Korea, adding that such remarks cannot be accepted under freedom of speech.

Rep. Park Jie-won, the floor leader of the minor People's Party, stressed people defaming the movement are hurting public unity and sparking social discord.

In addition to the stiff penalties, the opposition has called for making "March for the Beloved" the official song of the May 18 movement, which would oblige everyone attending the national ceremony in Gwangju to sing it.

Earlier this year, the conservative bloc opposed such calls over the song that commemorates the 1980 uprising.

Since 1997, the uprising's signature song had been sung at the event, but the government of former President Lee Myung-bak decided in 2009 to have a choir perform the song and allow those that wanted to sing along to do so. (Yonhap)