Lee Jae-myung wins South Korea's presidential election

South Korea's liberal party candidate, Lee Jae-myung, was elected president in Tuesday's snap election, six months to the day after he evaded military cordons to vote against a shock martial law decree imposed by his ousted predecessor.

Lee's victory stands to usher in a political sea change in Asia's fourth-largest economy, after the backlash against the martial law brought down Yoon Suk Yeol, the conservative outsider who narrowly beat Lee in the 2022 election.

Nearly 80% of South Korea's 44.39 million eligible voters cast their ballots, the highest turnout for a presidential election in the country since 1997, with Lee terming the polls "judgment day" against Yoon's martial law and the People Power Party's failure to distance itself from that decision.

With more than 99% of the votes counted, the Democratic Party's Lee stood at 49.3% to PPP candidate Kim Moon-soo's 41.3%, according to National Election Commission data.

A subdued Kim conceded the race and congratulated Lee in brief remarks to reporters.

Lee had long been favoured to win, and his supporters erupted in cheers as exit polls by the country's major broadcasters showed him defeating Kim by wide margins.

In a brief speech to supporters gathered outside parliament after the polls closed, Lee said he would fulfil the duties of the office and bring unity to the country.

"We can overcome this temporary difficulty with the combined strength of our people, who have great capabilities," he said.

He also vowed to revive the economy and seek peace with nuclear-armed North Korea through dialogue and strength.

The martial law decree and the six months of ensuing turmoil, which saw three different acting presidents and multiple criminal insurrection trials for Yoon and several top officials, marked a stunning political self-destruction for the former leader and effectively handed the presidency to his main rival.

Yoon was impeached by the Lee-led parliament, then removed from office by the Constitutional Court in April, less than three years into his five-year term, triggering the snap election that now stands to remake the country's political leadership and foreign policies of a key U.S. ally.