By Manuel Mogato and Stuart Grudgings
PHNOM PENH (Reuters) - Southeast Asian nations displayed a rare show of unity on Sunday against China's sweeping maritime claims, calling for the first formal talks with Beijing over a sea dispute that has raised tensions and exposed deep divisions in the region.
As Chinese Premier Wen Jiabao arrived in Cambodia for meetings with Southeast Asian leaders, the 10-member Association of Southeast Asian Nations (ASEAN) appeared determined to avoid a repeat of an embarrassing breakdown of talks in July over competing claims in the mineral-rich South China Sea, its biggest security challenge.
Cambodia's Prime Minister Hun Sen will tell Wen that ASEAN wants to begin talks on a binding Code of Conduct, aimed at reducing the chance of naval flashpoints, as soon as possible, ASEAN Secretary General Surin Pitsuwan told reporters.
"Prime Minister Hun Sen himself will be discussing with the PM of China tonight and delivering this consensus on the ASEAN side," Surin said.
"They would like to see the commencement of the discussion as soon as possible because this is an issue of interest, concern and worry of the international community."
China's assertive claims in the South China Sea have sown deep divisions within the bloc at a time when military spending in the region is surging and the United States refocuses attention on Asia - a "pivot" that President Barack Obama will reinforce on his visit to the summit on Monday in Cambodia's capital, Phnom Penh.
Chinese ally Cambodia has used its powers as ASEAN chair this year to restrict discussion of the issue, in line with Beijing's view that the disputes should be discussed on a bilateral basis. China has said it is willing to discuss the Code of Conduct when the "time is right."
Asked about the ASEAN request for formal talks, Chinese foreign ministry spokesman Qin Gang said consultations with ASEAN nations were ongoing and that the issue should not be a "stumbling block" for relations between China and the region.
Wen is due to hold formal talks with ASEAN leaders on Monday.
Diplomats said the Philippines, a close U.S. ally, had invited fellow Southeast Asian claimant states Vietnam, Brunei, and Malaysia to separate talks in Manila to be held later this year or early next year.
"We are trying to make that happen, hopefully in Manila," Philippine Foreign Secretary Albert del Rosario told reporters.
The other members of ASEAN include Cambodia, Laos, Myanmar, Thailand, Singapore and Indonesia, none of which have claims on the South China Sea.
One Philippine diplomat said the meeting was aimed at resolving issues among the claimant states, such as overlapping economic zones. He voiced frustration with China for delaying the start of talks with ASEAN over the Code of Conduct.
"ASEAN has done its part," the diplomat said. "Now it is up to China to also come up with its own because when we formally sit down we will present our position to them. In fact we have already written it."
Despite saying it is ready for talks with China, ASEAN is still debating its own version of a maritime code - a process that could be further complicated by the talks in Manila.
China's Wen arrived in Phnom Penh on Sunday for talks with ASEAN leaders ahead of the broader East Asia summit that includes the United States and Japan among other Asian nations.
Ahead of the summit, China warned that the South China Sea issue should not overshadow the talks. But U.S. officials said that Obama will reinforce a "very strong interest" in progress on a dispute-management mechanism, a likely irritant to China which has said that Washington should stay out of the row.
The facade of ASEAN unity on the issue collapsed dramatically in July when the group failed to agree on a joint communique for the first time in its 45-year history. Tempers frayed as Cambodia blocked a Philippine request to include a mention of a stand-off between Chinese and Philippine ships at a disputed shoal off the Filipino coast.
Philippine President Benigno Aquino refrained from mentioning the shoal incident in remarks to other leaders on Sunday.
Regional giant Indonesia took the lead in repairing the damage by circulating a six-point ASEAN consensus on the dispute that reaffirmed a commitment to complete the Code of Conduct.
Indonesia said on Friday it had proposed a kind of regional hotline with China that would enable leaders to "pick up the phone and chat" in the event of a naval incident.
Security analysts say the chances of a misstep leading to conflict are rising as military spending in the fast-growing region surges and nationalist sentiment over the dispute increases in several claimant states.
Proven and undiscovered oil reserve estimates in the South China Sea range as high as 213 billion barrels of oil, the U.S. Energy Information Administration said in a 2008 report. That would surpass every country's proven oil reserves except Saudi Arabia and Venezuela, according to the BP Statistical Review.
(Additional reporting by James Pomfret; Editing by Jason Szep and Raju Gopalakrishnan)