* U.S. envoy Bosworth meets South Korean officials
* Bosworth heading to Beijing, Seoul cautious on talks
* Six-party talks wanted, but success seen elusive
(Adds S.Korean foreign minister quotes, additional comment) By Sylvia Westall
SEOUL, Jan 5 (Reuters) - The U.S. has stepped up pressure on China to rein in its long-time ally North Korea, sending its envoy to Beijing on Wednesday as part of a campaign to push the North to end its nuclear programme.
The U.S. envoy for North Korea policy, Stephen Bosworth, met South Korean officials in Seoul before heading to China.
Washington hopes talks on dismantling North Korea's nuclear work can start soon, though a breakthrough may prove elusive.
Tension on the Korean peninsula has spiked to some of its highest levels since the 1950-53 Korean War after last year's sinking of a Southern ship which killed 46 sailors, an exchange of artillery fire, nuclear revelations and threats of war.
President Barack Obama's national security adviser met China's foreign minister on Tuesday in Washington and looked at ways to could persuade North Korea to abandon nuclear weapons work and "avoid destabilizing behaviour", the White House said. China and the United States must get parties back to talks and present ways to soothe tensions, Seoul's JoongAng Daily said.
"A war in the region would be catastrophic for not only the two Koreas, but their respective allies, the United States and China," it said in an editorial. In Seoul, U.S. envoy Bosworth met South Korea's foreign minister and nuclear negotiator. Bosworth does not appear to be in the region to unveil a U.S. proposal to get the North back to negotiations, but said he is collecting views from all sides.
Consultations are likely to focus on whether to restart disarmament-for-aid talks involving the United States, the Koreas, Japan, China and Russia.
Asked whether the U.S. was putting pressure on Seoul, Bosworth said: "Never." He gave no more comments. He will arrive in China later on Wednesday, and be in Japan on Thursday.
Speaking after his meeting with Bosworth, South Korea's foreign minister sounded a cautious note about whether the six-party talks could restart, calling them a "useful negotiating tool" for disarming North Korea.
"But the right conditions, including North-South dialogue are needed for there to be real progress," Kim Sung-Hwan was quoted as saying by news agency Yonhap. "It depends on the North's behaviour whether it will choose path of conflict or peace."
The flurry of diplomatic activity comes ahead of a meeting between Obama and Chinese President Hu Jintao this month, when North Korea will be a central topic.
In recent days all sides have suggested they are willing to restart the six-party talks which collapsed over two years ago when North Korea walked out.
Pyongyang is keen to return to the negotiating table where in the past it has won substantial aid after ratcheting up tensions.
"The Korean nation should defuse the confrontation between the north and the south at an early date," North Korea's official Rodong Sinmun newspaper said on Wednesday, according to quotes carried by state news agency KCNA.
Relations between the rival Koreas could not improve "as long as the said relations remain in the state of confrontation and on the brink of war without dialogue, contact and cooperation."
Analysts say North Korea's provocations in 2010, and China's protection of it from serious consequences, left Washington, Seoul and Tokyo more closely aligned in policy than ever before, which may make it easier for them to approach Pyongyang.
Still, observers question whether the North, which has tested nuclear devices twice in recent years, will be prepared to give up its atomic work which it sees as a cornerstone of a "military first" policy, and a powerful international bargaining chip.
(Editing by Daniel Magnowski)