Voters in South Korea will go to the polls on Tuesday to choose a new president. Candidates from the ruling and opposition parties will make their final pitch to voters on Monday, the campaign's final day.

The two leading candidates are Lee Jae-myung of the largest opposition Democratic Party and Kim Moon-soo of the conservative ruling People Power Party.

Opinion polls have suggested that Lee is the frontrunner, with Kim trailing behind.

But the results of a Gallup Korea survey released on May 23 showed that the gap between the two had narrowed to 9 percentage points.

Kim's supporters have been calling for Lee Jun-seok of the minor conservative Reform Party to drop his candidacy to unify conservatives behind Kim.

But the attempt has failed as the 22-day campaign period comes to an end.

Vote counting is scheduled to start as soon as the ballot boxes are closed on Tuesday.