Voter turnout in Wednesday's local elections reached a provisional 56.8 percent, the highest in 16 years, the nation's election watchdog said.

More than 23.4 million out of over 41.2 million eligible voters went to polling stations across the country to pick a total of 3,952 officials, including the mayor of Seoul, according to the National Election Commission.

The preliminary voter turnout is the highest since 1998, when 52.3 percent was recorded, and the second-highest ever. The highest voter turnout was posted in 1995, when a record 68.4 percent came out to vote in South Korea's first nationwide local elections.

This year's voter turnout was also higher than 51.6 percent in 2006 and 54.5 percent 2010, but it failed to top the 60 percent mark forecast by the NEC, amid low-key campaigns following the deadly ferry disaster.

The polls, widely seen as a referendum on President Park Geun-hye's performance, come as South Korea is still reeling from April's ferry disaster that has claimed nearly 300 lives and has battered public confidence in the government due to its botched handling of the tragedy.

By region, South Jeolla Province saw the highest preliminary voter turnout of 65.6 percent, followed by the southern resort island of Jeju with 62.8 percent.

The election watchdog said the official voter turnout would likely be available by early Thursday. (Yonhap)