* China's foreign minister meets N.Korean counterpart
* U.S., South Korea say passing of sanctions a good outcome
* U.S. says China must ensure sanctions implemented
* ASEAN at impasse on wording of S. China Sea in communique (Adds new details, comments throughout)
MANILA, Aug 6 (Reuters) - China's foreign minister said on Sunday new U.N. Security Council sanctions on North Korea were the right response to a series of missile tests, but dialogue was vital to resolve a complex and sensitive issue now at a "critical juncture".
Wang Yi said the U.N. resolution's call for a return to talks emphasised that diplomatic and peaceful means were necessary to avoid tensions and it was necessary to prevent the crisis from escalating.
The U.N. Security Council unanimously imposed new sanctions on North Korea on Saturday that could slash by a third the Asian state's $3 billion annual export revenue over Pyongyang's two July intercontinental ballistic missile tests.
"After the implementation of the resolutions, the Korean peninsula issue enters into a critical juncture," Wang told reporters on the sidelines of a regional foreign ministers' meeting in Manila.
"We call on all sides to take a responsible attitude when making judgements and taking actions.... We cannot do one and neglect the other. Sanctions are needed but sanctions are not the final goal," Wang said.
North Korea has been under U.N. sanctions since 2006 over its ballistic missile and nuclear programs. The new measures were a response to five nuclear tests and four long-range missile launches.
The latest, U.S.-drafted resolution bans North Korean exports of coal, iron, iron ore, lead, lead ore and seafood and prohibits countries from hiring additional North Korean labourers. It also bans new joint ventures with North Korea.
The North Korea standoff is expected to dominate Monday's ASEAN Regional Forum (ARF), which gathers 27 foreign ministers - including those of Russia, Japan, the United States, China and North and South Korea - to discuss security issues.
Wang met his North Korean counterpart Ri Yong Ho on Sunday for bilateral talks that started off in a cordial way, with Ri smiling continuously as the two shook hands. Wang placed his hand on Ri's shoulder as the two entered a meeting room.
"We actually had very thorough talks," Wang said afterwards. "The Chinese side urged the North Korean side to calmly handle the resolutions the U.N. Security Council just made towards North Korea and to not do anything unbeneficial towards the international community such as a nuclear test."
He declined to say what Ri had told him.
Wang earlier said it was important that Ri is attending the Manila meetings "so he can listen to suggestions from various parties and has the right to present his views."
But it was not immediately clear if Ri planned to meet ministers of other countries in Manila. South Korean Foreign Minister Kang Kyung Wha expressed hope the two could talk.
Kang met with U.S. Secretary of State Rex Tillerson on Sunday and both expressed satisfaction with the passing of the tougher U.N sanctions. Tillerson described it as a "a good outcome" and Kang weighed in, adding it was "it was a very, very good outcome."
The United States, which has long maintained that China has not done enough to rein in North Korea, negotiated with China for a month on the new resolution.
Susan Thornton, acting Assistant Secretary of State East Asian and Pacific Affairs, said in Manila that China's support showed it recognised the gravity of the situation, but it was incumbent upon Beijing to ensure the sanctions were implemented.
COMPLEX AND SENSITIVE
Wang said there was now a "high level of sensitivity and complexity" that had hurt China's relations with North Korea.
He said he hoped all parties involved could seriously consider China's dual suspension proposal, whereby North Korea halts its nuclear and missile tests and for South Korea and the United States to stop joint military drills.
"This is currently the most realistic and plausible initiative and it is the most reasonable and friendly solution," he said.
U.S. Ambassador to the United Nations Nikki Haley ruled that out on Saturday, saying Washington would continue to take "prudent defensive measures", including joint military drills with South Korea.
Separately, Southeast Asian officials were still trying to reach consensus on a customary communiqué that was supposed to have been released on Saturday, reflecting differences about how to address disputes involving Beijing in the South China Sea.
According to several diplomats from the Association of South East Asian Nations (ASEAN), Vietnam wanted the text to explicitly oppose the building and militarisation of artificial islands in disputed waters.
China is sensitive about ASEAN including even veiled references to the expansion of its military capabilities on the islands.
ASEAN's problem in agreeing the wording highlight China's growing influence at a time of uncertainty over the new U.S. administration's policy on the South China Sea and to what extent it will contest China's assertiveness.
(Additional reporting by Joseph Campbell and Manuel Mogato; Writing by Martin Petty; Editing by Bill Tarrant)