South Korean opposition leader Lee Jae-myung has declared his bid for the presidency, promising to fix inequality and spur economic growth.

In a video published on Thursday, Lee committed to address economic polarization, which he said was a major source of societal discord, emphasizing how he believed it had compounded recent political turbulence, Al Jazeera reported.

The presidential election was slated for June 3, after former President Yoon Suk Yeol's impeachment for declaring martial law in December was affirmed by the constitutional court on April 4.

Lee, the frontrunner in polls, promised to pursue large-scale government investments in technology and talent development to revitalize the economy, according to Al Jazeera.

Conservative opponents have warned that the opposition's return to power could weaken the alliance with the US and jeopardize improved relations with Japan, but Lee recommended a realistic approach to diplomacy.