(Recasts with adoption of the joint declaration against marine debris, adds Thai government comment on regional economy)
By Patpicha Tanakasempipat and Panu Wongcha-um
BANGKOK, June 22 (Reuters) - Southeast Asian nations vowed on Saturday to fight against plastic pollution in the ocean, as their leaders adopted a joint declaration during a summit in Bangkok.
The Bangkok Declaration on Combating Marine Debris in ASEAN Region was adopted by leaders of the 10-member Association of Southeast Asian Nations (ASEAN), which includes four of the world's top polluters.
ASEAN members Indonesia, the Philippines, Vietnam and Thailand, along with worst offender China, throw the most plastic waste into oceans, according to a 2015 report co-authored by environmental campaigner Ocean Conservancy.
"All countries...value and emphasize environmental protection and support Thailand in including the agenda on safeguarding of the environment and combating marine debris, which matches a global agenda," deputy government spokesman Werachon Sukondhapatipak told reporters on Saturday.
The declaration was commended by environmentalists as a good first step for the region, though doubts remained that implementation will be a challenge because the group has a code of non-interference that would leave necessary policymaking in the hands of individual member countries.
The 10 ASEAN countries vow to "strengthen actions at the national level as well as through collaborative actions...to prevent and significantly reduce marine debris," according to the official document seen by Reuters.
They will also "strengthen national laws and regulations as well as enhance regional and international cooperation including on relevant policy dialogue and information sharing".
Neither the declaration nor its accompanying Framework of Action specifically mention bans on single-use plastic or imports of foreign waste, as environmental groups previously demanded ahead of the summit.
The declaration came ahead of next week's G20 summit in Japan, which assembles 20 major economies and will also aim to tackle marine plastic pollution.
The China-originated Regional Comprehensive Economic Partnership (RCEP) pact was expected to be finalised this year, Werachon said.
Negotiations began in 2012 on RCEP, which envisions the creation of a free trade zone encompassing 45 percent of the world's population and more than a third of its GDP, but does not involve the United States.
"Every country emphasizes the importance of the RCEP negotiation. All leaders agreed that it should be completed this year," he said.
"This mechanism will strengthen ASEAN economically and can be linked up with other regional economic cooperation frameworks."
First proposed by China, RCEP currently has 16 signatories: ASEAN and six Asia-Pacific countries, including major economies India, Japan and South Korea.
ASEAN has existing free-trade agreements with all six countries.
"We must turn to help each other more. Internal trade within ASEAN must increase in value," said Werachon.
Formed more than 50 years ago, ASEAN has historically struggled with challenges facing the region because it works only by consensus and is reluctant to become involved in any matter regarded as internal to a member state.
The top leaders did not discuss the South China Sea dispute, but the topic will likely come up on Sunday, Werachon added.
However, the issue was discussed by the foreign ministers earlier on Saturday. Thailand's foreign ministry spokeswoman said the countries made progress on a Code of Conduct negotiating draft for the disputed South China Sea and likely will finish a first reading by the end of this year.
The claims on the South China Sea - one of the world's busiest waterways - asserted by ASEAN members the Philippines, Vietnam, Malaysia, Brunei and Indonesia as well as China and Taiwan make it a potential flashpoint.
China says it owns most of the waterway and has been aggressively building and militarising artificial islands as well as confronting ships that enter the zone, actions that give urgency to ASEAN's efforts negotiate on the area.
"There is real risk that developments on the ground - or more precisely at sea - are far outpacing the COC's progress thereby possibly rendering it irrelevant," said Marty Natalegawa, a former foreign minister of Indonesia.
(Reporting by Patpicha Tanakasempipat and Panu Wongcha-um; Additional reporting by Kay Johnson and Panarat Thepgumpanat; editing by John Stonestreet and Marie-Louise Gumuchian)
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