A win for the left-of-center frontrunner in South Korea’s presidential election would likely herald more caution by Seoul over taking sides in US-China rivalry, a new effort to draw North Korea into dialogue and the potential for tension with Japan.

South Korea's liberal presidential candidate Lee Jae-myung said on Monday he would pursue the restoration of communication between Seoul and North Korea, including via a military hotline if elected.

South Korea's liberal frontrunner for president Lee Jae-myung was leading his main conservative rival Kim Moon-soo by more than 10 percentage points in an opinion poll issued on Tuesday, though the race had tightened a week ahead of the election.