Moon's remarks came on the one-year anniversary of so-called candlelight rallies which were first staged a year earlier in protest of the then-President Park Geun-hye government. She was later ousted from her presidency and is currently being tried on charges of corruption and influence peddling.

"The push is intended to wash off old (power) abuses and perform politics honestly so as to make a just country out of the Republic of Korea," Moon noted.

Social evils from the past have also pushed the country into a trap of stagnant economic growth, he also pointed out, adding that the anti-corruption push would also help rejuvenate the national economy.

Around 50,000 South Koreans gathered in central Seoul late Saturday for mass demonstrations to mark the anniversary.

Videos of the candlelight rallies from a year ago were played along with a music concert in the Saturday rallies in Gwanghwamun Square where the protests were originally held.

Participants cried out for social reformation efforts and corruption eradication to carry on with the spirit of the candlelit protest a year ago.

Some of them staged a street march toward the nearby presidential office of Cheong Wa Dae, calling for the withdrawal of the U.S. Terminal High Altitude Area Defense system recently deployed in the southern county of Seongju, as well as the cancellation of a 2015 deal with Japan to settle Japan's wartime crime of sexually enslaving Korean women.

"My thanks and respect go to the people of South Korea who gave an opportunity to make this great history possible," Choo Mi-ae, chairwoman of the ruling Democratic Party, said while joining the rally with other party members and Seoul Mayor Park Won-soon.

Another mass rally was staged in Yeouido where nearly 10,000 participants expressed support for Moon and investigating former President Lee Myung-bak for corruption. (Yonhap)