The discord was widely attributed to political pressure from China, which would rather deal separately with the five nations with which it has maritime disputes.
Analysts say continued efforts to unify Southeast Asian nations on the issue of territorial disputes in the South China Sea are being complicated by Beijing's rising influence in the region.
ASEAN, a bloc of 10 Southeast Asian nations, for the first time in its 45 year history failed to produce a joint statement at a regional summit in Cambodia last week, revealing a deep rift over the issue.
The discord was widely attributed to political pressure from China, which would rather deal separately with the five nations with which it has maritime disputes, rather than confront ASEAN as whole.
Indonesian Foreign Minister Marty Natalegawa is on an emergency tour of Southeast Asia, a trip he describes as an attempt to "restore ASEAN cohesion and unity on the South China Sea." Speaking in Cambodia Thursday, he said some progress is being made.
"ASEAN centrality requires - demands - ASEAN unity. And the fact is, despite suggestions to the contrary, in actual fact, ASEAN remains united, ASEAN remains cohesive. And therefore, ASEAN remains able to fulfill its role as in the central and driving seat of our region," said Marty Natalegawa.
But many say unity is not likely to be achieved with China continuing to exert enormous political pressure on nations like Cambodia, which rely on Beijing for billions of dollars in economic assistance.
Ralph Cossa, a security analyst at the Pacific Forum in Hawaii, says such pressure could eventually work against China.
"I think China wants ASEAN to not unite," he said. "But I don't think China wanted to see it go to the extreme that it did, where essentially now the spotlight is shining on China's bullying of Cambodia and some of the weaker ASEAN countries."
Many ASEAN members blame Cambodia, currently the bloc's chair, for giving into Chinese pressure by rejecting a proposal by the Philippines and Vietnam to mention their territorial disputes with China in the group statement.
Phat Kosal, an Asia researcher at the University of Southern California, says Vietnam is upset that Cambodia chose to side with China, breaking their traditional alliance.
"I think there must be some kind of resentment [on behalf of Vietnam], but not to the level that there is a split in the future because Vietnam knows that Cambodia cannot do much as it is so much under China's pressure. Cambodia needs assistance to develop its economy," said Phat Kosal.
Brad Adams, Asia director at Human Rights Watch, says it is clear that Cambodian Prime Minister Hun Sen, in siding with China over Vietnam, is not putting his country's interest first.
"Hun Sen is showing that he is going to make alliances with the people he thinks serve his interest the best," he said. "I don't think he makes alliances thinking that they serve the country's interest the best. I think it's almost always about what serves his political interest and personal interest the best."
Observers say short-term attempts to build regional consensus on the South China Sea may ultimately prove futile, even during the next ASEAN summit in November.
But the issue is likely to return to ASEAN's agenda next year, when Brunei - a claimant in the South China Sea - takes its turn as the rotating head of the regional bloc.
Some information for this report was provided by AP and Reuters.