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.

Lee Jae-myung, the presidential candidate for South Korea's Democratic Party, poses for photographs as he casts his early vote for the upcoming presidential election with his supporters at a polling station in Seoul,

South Koreans go to the polls on June 3 to elect the country's 21st president, aiming to restore political stability after months of turmoil and fill a power vacuum following the botched attempt by former leader Yoon Suk Yeol to impose martial law.