The meetings will be attended by Ministers from the 10 Association of Southeast Asian Nations (ASEAN) countries - Brunei Darussalam, Cambodia, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand, Viet Nam.
They urged South China Sea claimants "to refrain from land reclamation, construction of outposts, militarisation of disputed features and undertaking unilateral actions that caused permanent physical change to the marine environment in areas pending delimitation, " the statement said.
Tensions on the Korean Peninsula have overshadowed discussions at the annual Association of South-East Asian Nations ministerial meetings in Manila, which were being held on Saturday as the regional bloc was to mark its 50th founding anniversary.
The top diplomats of the US, Australia and Japan also called on their Southeast Asian counterparts to negotiate a legally binding COC in the disputed waters.
Wang told a news conference in Manila that those conditions include non-interference by outside parties, an apparent reference to the United States, which China has frequently accused of meddling in an Asian dispute that should be resolved only by the countries involved.
However, few officials and experts believe the negotiations will go smoothly and lead to new rules of behaviour in the disputed sea anytime soon.
The three nations also called on China and the Philippines to respect last year's worldwide arbitration ruling which dismissed much of Beijing's claim in the sea.
ASEAN ministers said in a communique Sunday they "warmly welcome improving cooperation" with China and are ready to begin substantive negotiation on the code of conduct, but made no mention of making it binding.
The ministers had been debating for at least two days on how to respond to China collectively, with Vietnam said to be strongly resisting an agreement on the framework for a code of conduct as pushed by Beijing. Under the circumstances, Kono called for the ASEAN members' cooperation for a peaceful solution to the South China Sea issues, by explaining Japan's position at Sunday's meeting, sources with access to the talks said.
The US and other nations have tested Beijing's claims by conducting "freedom of navigation" operations around islands controlled by China.
But Harris offered nothing more than moral support to Southeast Asia. The problem is that no other country is willing to directly confront China, since it is economically and militarily more powerful and probably the most powerful in South East Asia.
But in recent years Beijing has managed to weaken regional resistance by courting some ASEAN members.
The ministers from the three Asia-Pacific powers "reiterated that the three countries will continue to fly, sail, and operate wherever global law allows".
The role of the Philippines as 2017 chair of Asean has helped China keep a lid on discord.