Japan's former Prime Minister Shinzo Abe beat his rival ex-Defense Minister Shigeru Ishiba to win the presidential election of the main opposition Liberal Democratic Party (LDP) here Wednesday.

Japan's former Prime Minister Shinzo Abe

Abe won the run-off following the initial round when none of the five candidates secured a majority of votes.

Abe captured 108 out of 197 valid ballots against 89 by Ishiba in the run-off involving only LDP lawmakers.

Ishiba was the strongest contender in the first round of the election, clinching 199 votes against 141 bagged by Abe, but still short of the majority threshold of 250 votes.

In a short speech after being declared the new party chief, Abe said he would do his utmost to forge party unity and lead it to victory in the next general election due within a year.

The triumph makes 58-year-old Abe, who headed the LDP between 2006 and 2007, the front-runner for the post of Japan's next prime minister, given that recent opinion poll suggested the LDP could form the largest political force in the House of Representatives when the ruling Democratic Party of Japan is ousted from power in the next general election.