TOKYO, Sept. 28 (Xinhua) -- Japanese Prime Minister Shinzo Abe on Thursday dissolved the more powerful lower chamber of Japan's bicameral parliament and called a general election.

The general election will be held on Oct. 22, with official campaigning set to start on Oct. 10.

Abe dissolved the lower house as soon as it convened at noon (local time) for an extraordinary session.

Much to the chagrin of opposition parties, Abe made no policy speech, shirked any parliamentary debate and held no press conference afterwards.

The overall timing of the dissolution and calling of a snap election, observers have said, is to not allow the opposition camp enough time to fully prepare for the upcoming general election.

However, Tokyo Gov. Yuriko Koike's newly-formed Party of Hope may see an effective merger with the main opposition Democratic Party to better stand against the ruling Liberal Democratic Party-led (LDP) bloc in the upcoming campaign.

Democratic Party leader Seiji Maehara, just three weeks into his tenure, has had to contend with disunity and defections from his party, but has intimated that his party may also join forces with the minor opposition Liberal Party, headed by political heavyweight Ichiro Ozawa.

Abe said Monday that the dissolution of the lower house and calling of a snap election is in essence to seek a mandate on his policies to address Japan's rapidly aging society, falling birth rate and issues of security related to tensions on the Korean Peninsula.

The prime minister recently unveiled a 2 trillion yen (17.8 billion U.S. dollars) policy package to be paid for by an allocation of revenue generated from a tax hike slated for 2019, to service ballooning social welfare costs.

Abe last dissolved the lower house of parliament in November 2014 and thereafter led the LDP and its junior Komeito coalition ally to a sweeping victory in the following election in December.

Thursday's dissolution marks the 4th time in postwar Japan that the lower chamber has been dissolved on the day the Diet has convened.

The Japanese leader could theoretically serve until 2021 if he is reelected as party leader next year.

This would make him the longest-serving prime minister in Japanese history.

Recent polls, however, have shown that the majority of voters are opposed to this idea.

The public have also been opposed to the calling of a general election within the period of which the prime minister's last term would have naturally run its course, the latest polls revealed.

Abe has also been accused by opposition parties and the public of calling the snap election as a means of merely extending his grip on power.

Claims that Abe has dissolved the lower house at this juncture have also been leveled at the premier as a strategy by him to avoid having to answer multiple allegations of cronyism by the opposition camp during parliamentary debate.

The Japanese premier has said he will step down if his ruling LDP fails to secure a basic majority in the polls next month.

The ruling coalition currently controls 68 percent of seats in the 475-member lower house, including 288 for the LDP and 35 for its coalition partner Komeito.

The total number of seats, however, is set to be reduced to 465 in the next election as part of a reform aimed at reducing the excessive weight given to rural votes under the current system.

Since the recent shake up in national politics, Abe has, of late, been muted on his contentious plans to amend Japan's pacifist constitution following a national referendum.