There are low expectations of any major breakthroughs at the meeting, but the leaders have expressed hopes it could help revitalise three-way diplomacy and ease regional tensions.

South Korean President Yoon Suk Yeol, Chinese Premier Li Qiang, and Japanese Prime Minister Fumio Kishida will meet Monday for talks, with Pyongyang's announcement that it will launch a satellite by June 4 likely to make it onto the agenda.

North Korea informed the Japanese Coast Guard of an eight-day launch window, which began at midnight Sunday into Monday.

It designated three maritime danger zones near the Korean peninsula and the Philippines' main island of Luzon where the satellite-carrying rocket's debris might fall, according to the Kyodo news agency.

North Korea is barred by multiple UN resolutions from tests using ballistic technology.

Analysts say there is significant technological overlap between space launch capabilities and the development of ballistic missiles.

After the leaders' summit, Yoon, Li and Kishida will hold a press conference, before joining a business summit aimed at boosting trade between the countries, which will also be attended by top business leaders.

Experts have warned that, due to the three countries' starkly divergent positions on key issues including Pyongyang's nuclear threats and growing ties with Russia, it will be hard for them to form a consensus.

"Despite the challenges in organising this meeting, it is unlikely to produce significant diplomatic achievements," South Korea's Hankyoreh newspaper said in an editorial Monday.

"Nevertheless, this meeting is important because it is the only regular communication channel where the leaders of South Korea and Japan, both allies of the United States, can meet with the Chinese leader," it said.

Seoul should use the trilateral meeting "to overcome the limitations of the tilted diplomacy with Washington and Tokyo and reconstruct the framework of trilateral diplomacy of South Korea, China and Japan, which has been out of favour for some time," Hankyoreh said.

President Xi Jinping is China's top leader, with Li serving under him as premier.

China is North Korea's largest trading partner and a key diplomatic ally, and it has previously resisted condemning Pyongyang for its weapons tests, instead criticising joint US-South Korea drills for raising tension.

Nuclear-armed North Korea launched its first reconnaissance satellite last November in a move that drew international condemnation, with the United States calling it a "brazen violation" of UN sanctions.

Seoul said on Friday that South Korean and US intelligence authorities were "closely monitoring and tracking" presumed preparations for the launch of another military reconnaissance satellite.