China's premier said on Wednesday major powers must oppose a new Cold War, a thinly veiled reference to Washington as top Asian and US officials gathered for talks in Indonesia.

Beijing has expressed concern about US-backed blocs forming on its doorstep, while facing disputes with other powers in the region over the South China Sea and other issues.

"Disagreements and disputes may arise between countries due to misperceptions, diverging interests or external interferences," Li Qiang said at the start of an ASEAN-plus-three meeting with Japan and South Korea in Jakarta.

"To keep differences under control, what is essential now is to oppose picking sides, to oppose bloc confrontation and to oppose a new Cold War."

The 10-member Association of Southeast Asia Nations (ASEAN) is holding separate summits with China, Japan, South Korea, the United States and Canada, providing an arena for big powers to lobby the bloc and their rivalries to play out.

US Vice President Kamala Harris is attending in place of President Joe Biden, while Li was taking part instead of President Xi Jinping.

Wednesday's meetings come before an 18-member East Asia Summit on Thursday to be attended by Russian Foreign Minister Sergei Lavrov, where broader geopolitical issues are expected to top the agenda.

The Russian embassy in Indonesia posted an image of Lavrov arriving in Jakarta on Wednesday.

"The vice president will underscore the United States' enduring commitment to the Indo-Pacific generally and to ASEAN centrality specifically," US National Security Advisor Jake Sullivan told reporters Tuesday, using another term for the Asia-Pacific region.

Japanese Prime Minister Fumio Kishida and South Korean President Yoon Suk Yeol are attending both days of meetings.

- 'Undermine peace' –

Yoon reportedly told ASEAN leaders there must be no cooperation with North Korea, which the United States said this week is holding arms talks with Russia.

"Any attempts to forge military cooperation with North Korea, which is acting to undermine peace in the international community, should be immediately stopped," Yoon was quoted by a presidential official as telling an ASEAN meeting, according to Yonhap news agency.

Kishida and Yoon met Li, with a row between China and Japan over the release of treated wastewater from the damaged Fukushima nuclear plant expected to be prominent.

Host Indonesia told an ASEAN leaders' summit on Tuesday that the bloc would not become a proxy for big power competition as US-China tensions continue to flare over Taiwan, the South China Sea and Russia's invasion of Ukraine.

The roundtable involving Lavrov and Harris will be the first high-level US-Russia encounter since a foreign ministers' meeting in Jakarta in July, where US and European officials rounded on Moscow's top diplomat over the Ukraine conflict.

A Southeast Asian diplomat present at Wednesday's meetings told AFP they would conclude with joint statements about closer diplomatic, economic and food security collaboration between the powers and ASEAN.

ASEAN leaders will host summits on Thursday with Indian Prime Minister Narendra Modi, Australian Prime Minister Anthony Albanese and United Nations Secretary-General Antonio Guterres.

Albanese told a regional forum in Jakarta on Wednesday Canberra is seeking closer engagement and economic ties with Southeast Asian nations.

- 'Severest consequences' –

Myanmar will also be a major issue at the summits with China -- a key diplomatic ally of the junta in the former Burma.

Southeast Asian leaders strongly condemned the violence and attacks on civilians in Myanmar on Tuesday, directly blaming the junta.

China also upset several ASEAN members last week when it released a new official map claiming sovereignty over the majority of the South China Sea.

It sparked sharp rebukes from across the region, including Malaysia, Vietnam and the Philippines.

Japan said late Tuesday it had lodged a "strong protest" against Beijing over the map and called for its retraction, government spokesman Hirokazu Matsuno told a briefing.

The Southeast Asian diplomat who spoke to AFP said joint statements from the meetings will "contain references to the South China Sea and Myanmar".

Leaders were to express concern about "land reclamations, activities, serious incidents" in the disputed South China Sea, according to a draft ASEAN chair statement, seen by AFP, to be issued this week.

However, experts said ASEAN leaders were unlikely to confront Li to avoid angering Beijing.

"I predict... the leaders will avoid discussing confrontational issues such as China's new map," Aleksius Jemadu, a foreign affairs expert at Indonesia's Pelita Harapan University, told AFP.

"They won't risk the relationship with big powers."