Japan's ruling Liberal Democratic Party is stepping up preparations for its leadership race, with Prime Minister Shinzo Abe saying Friday constitutional revision will be a major issue in the election.

While Abe, who heads the party, was not clear about whether he will run in the presidential race in September and seek another three-year term, he said at a press conference on the de facto final day of the Diet session that he wants to "speed up discussions" on revising the Constitution.

Amending the postwar Constitution, including the war-renouncing Article 9, is a longtime political goal of the conservative party and of Abe.

As the country grapples with the aftermath of the torrential rain that devastated western Japan this month, Abe also pledged to accelerate government efforts to rebuild the affected areas.

"The central government will do its best in cooperation with municipalities so the survivors could resume their safe lives as soon as possible," Abe said.

The prime minister added he will visit Hiroshima, one of the hardest-hit prefectures, on Saturday to listen to the needs of disaster victims in the wake of the massive floods and landslides that claimed more than 220 lives.

Asked about whether the government will compile an extra budget for reconstruction measures, Abe said the government will first use around 400 billion yen ($3,600 million) in a reserve fund to deal with the matter.

After the Diet session formally ends on Sunday, Abe is expected to devote his energy to winning the LDP's presidential election, which would set the stage for him to become Japan's longest-serving prime minister.

Abe declined to say when he will announce his candidacy, merely saying he will consider the matter well "over the summer season."

Former LDP Secretary General Shigeru Ishiba, the party's policy chief Fumio Kishida and internal affairs minister Seiko Noda are also considered possible candidates. But so far they have not had enough support from LDP members to beat Abe.

Abe's government has now succeeded in pushing through bills, including a contentious bill that authorizes the opening of casino gambling in Japan, in the Diet controlled by the Liberal Democratic Party and its junior coalition partner Komeito party.

Shortly after the ordinary Diet session began Jan. 22, opposition lawmakers resumed grilling Abe over favoritism allegations related to a pair of school building projects carried out by people with ties to him or his wife Akie.

Opposition lawmakers and a majority of the public found Abe's explanations over the allegations in the Diet were inadequate, and his Cabinet struggled with lower approval ratings at one point.

The government also came under pressure in the wake of the Finance Ministry's falsification of official documents and sexual harassment against a TV reporter by a top bureaucrat of the ministry.

Despite risks of facing additional questions over the scandals, for the purpose of passing major government-sponsored bills, including one aimed at reforming working styles, the government extended the 150-day Diet period, which was originally scheduled to end June 20.

While a solid majority held by the ruling parties in the two Diet chambers made it possible for the government to pass the bills despite attempts by opposition parties to stop them, the Cabinet's approval ratings have somewhat picked up in recent months, staying above 40 percent.

On June 29, the labor reform bill was adopted, which consists of three key pillars -- setting a legal cap on overtime work, realizing "equal pay for equal work" for regular and nonregular workers and exempting skilled professional workers with high wages from working-hour regulations.

Opposition lawmakers criticized the third pillar as encouraging long working hours and leading possibly to an increase in "karoshi," or death from overwork.

On Wednesday, the Diet passed a bill to increase the number of upper chamber seats for the first time in nearly five decades.

The increase is widely seen as an LDP attempt to "bail out" its lawmakers who will not be able to run in the election next summer from their constituencies as a result of an electoral system reform.