South Korea's largest labor organization on Thursday said it will officially support presidential front-runner Moon Jae-in in the May 9 election.

The Federation of Korean Trade Unions, the larger of two umbrella labor groups here, said in a recent poll of its members that 46.97 percent backed the Democratic Party candidate. 

Among its 674,464 members, 351,099 took part in the survey conducted from April 10-25, it said.

The Korean Confederation of Trade Unions, a smaller and militant labor umbrella group, has decided to support two progressive candidates, Sim Sang-jeung of the Justice Party and Kim Sun-dong of the People's Union Party.

"We believe that Moon, who stood by the working class and poor masses as a labor and human rights lawyer, is the right person to solve our society's polarization and inequality issues," the FKTU said in a press release.

The group said it expects the candidate to fight for various labor issues, including raising the minimum wage and cutting working hours.

"We will use every means possible guaranteed under the law for Moon's election," it said.

According to a poll published by Realmeter earlier in the day, Moon garnered 44.4 percent, while Ahn Cheol-soo of the center-left People's Party gained 22.8 percent. The survey was conducted from Monday to Wednesday. (Yonhap)