Sanae Takaichi, Japan's former economic security minister, was elected leader of Japan's ruling Liberal Democratic Party (LDP) on Saturday and is now likely to become the country's first female prime minister, succeeding the outgoing Shigeru Ishiba.

Takaichi defeated Agriculture Minister Shinjiro Koizumi in a run-off held after none of the five candidates secured a majority in the first round of voting.

In the first round of voting, LDP parliamentarians cast 295 votes, matched by an equal number of votes from rank-and-file members. Takaichi led with 183 votes, advancing to a run-off against Koizumi, who garnered 164 votes.

In the run-off, lawmakers again cast 295 votes, but the rank-and-file members' votes were reduced to one for each of the LDP's 47 prefectural chapters. Takaichi won the runoff with 185 votes, defeating Koizumi, who received 156 votes.

Following the election, Takaichi said, "Rather than feeling happy, I see a really tough road ahead," urging lawmakers to work together to rebuild the party.

She added, "We will transform the LDP into a vibrant and energetic force."

Takaichi is expected to be elected Japan's new prime minister at a session of the Diet, or parliament, which will reconvene around Oct 15, according to Nikkei Asia.

Even though the ruling bloc has failed to secure a majority in both chambers of parliament, the new leader is almost certain to become Japan's next prime minister since the LDP remains the largest party.