The liberal Democratic Party on Thursday launched an investigation into a possible leak of information on the outcome of a poll that will make up a part of its in-house election to name its presidential candidate.

The move came one day after the party held a one-day polling of its electorate as part of its primary election for the May 9 presidential vote.

The party earlier said the outcome of Wednesday's vote will not be revealed immediately and instead be combined with telephone surveys and additional votes to be held later.

But many text messages suggesting one of four contenders for the party nomination swamped the nation shortly after the polling ended.

The outcome of the vote, or its possible leak, may not have any serious impact on the outcome of the entire primary process that is expected to involve more than 2 million citizens and party members.

Still, those said to be lagging in the race reacted angrily, noting such texts, whether true or not, may help further boost the popularity of the one said to be leading the race.

Rep. Yang Seung-jo, vice chief of the party's election commission, dismissed the alleged leak as groundless.

Still, the party will seek a prosecution probe into those responsible for the circulation of such messages should there be any, he told a press briefing.

About 100,000 pre-registered voters, including many non-party members, are said to have taken part in Wednesday's vote.

The four contenders competing for party nomination are former party chief Moon Jae-in, South Chungcheong Province Gov. An Hee-jung, Seongnam City Mayor Lee Jae-myung and Goyang Mayor Choi Sung.

The primary election will end April 3 when the country's largest party is set to hold a national convention in Seoul to name its single candidate. (Yonhap)