The LDP has ruled Japan nearly continuously since the 1950s, apart from a few years in the interim, and electoral success for Mr Abe next month would pave the way for him to become the longest serving prime minister in Japanese history.
On Monday, Abe had officially confirmed snap elections next month.
Mr Abe said at the event that he hoped to welcome Premier Li to Japan this year and "spur the development of our relationship" with bilateral meetings, Nikkei reported. "We have to cooperate with the worldwide community as we face the threat from North Korea".
Working in Abe's favor, he said, are the LDP's nationwide electoral organization and his handling of North Korea, which has sent two missiles over Japan in recent tests. "What is important is whether we can fight with a single voice".More news: Gov. Rauner signs bill expanding abortion coverage in IL
Instead, Seiji Maehara, the leader of the Democratic Party, urged members to run as candidates for a new party called Kibo no to (Party of Hope) which was launched only the day before by popular Tokyo governor Yuriko Koike.
On Monday Shinzo Abe, the prime minister, announced what seemed to be a routine snap election, meant to take advantage of the weakness of the opposition to secure four more years in power.
Opposition lawmakers scrambled to regroup around Tokyo Gov. Yuriko Koike's new party to challenge Abe's ruling party. Founding the Party of Hope was a bold strategic move, meant to pave the way for a return to national politics.
The head of the main opposition Democratic Party proposed to members that the DP should not run candidates in the October 22 poll and that they were free to join Koike's new group.More news: Hurricane Maria triggers storm warnings for NC coast
But she again stressed that she had no intention of taking in all members of the Democratic Party.
Still, a relatively good showing by her party could allow it to influence Abe on policies such as constitutional change, an issue both politicians have an interest in, said Stephen Nagy, a professor at International Christian University in Tokyo.
Abe enjoyed a healthy lead in the polls of more than 30 points only a week ago but the gap appeared to have narrowed following Koike's high-profile announcement.
A survey by the Mainichi newspaper showed 18 per cent of voters plan to vote for Ms Koike's party, compared to 29 per cent for LDP.More news: South Korea President calls for WARTIME CONTROL to fight Kim
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