The mayor of the South Korean capital Seoul has resigned after losing a referendum on free school lunches.

Oh Se-hoon's resignation Friday comes two days after he lost a citywide referendum that drew less than a third of the city's eligible voters, failing a legal requirement for counting ballots.

Oh, a conservative ally of President Lee Myung-bak, had staked his career on the referendum, which would have reversed a decision by the liberal city council to extend free lunches to all schoolchildren.

Oh had proposed to provide lunches only to the neediest 50 percent of schoolchildren.

The vote was seen as a test of the country's commitment to social welfare spending and the popularity of Oh's Grand National Party, which rules at the national level.