CEBU, Philippines, Jan 14 - Chinese Premier Wen Jiabao will visit Japan in April, officials said on Sunday, in the clearest sign yet that relations between Asia's biggest powers are on the mend.

Wen and Japanese Prime Minister Abe Shinzo used a regional summit in the central Philippines to firm up a timeframe for China's first state trip to Japan in over six years and to forge closer ties with South Korea.

The Association of South East Asian Nations (ASEAN), which wants to establish itself as a world player, urged the three countries to find fresh ideas to resolve the North Korean nuclear crisis and remove the threat of an atomic arms race in the region.

In their first trilateral meeting in two years, China, Japan and South Korea agreed to build on their thawing relations, saying they would further promote trade and energy security and regularly consult each other on key issues.

Relations with Japan's neighbours hit a nadir due to Abe's predecessor, Junichiro Koizumi, repeatedly visiting Tokyo's Yasukuni's war shrine, seen by critics as glorifying Japan's World War II militarism.

A Japanese government official said Wen and Abe made no mention of the shrine at their talks on the central resort island of Cebu, where leaders from 16 countries have been welcomed in a whirl of Filipino pageantry.

Wen invited Abe to visit China in the second half of the year, an offer the Japanese leader said he would consider depending on the outcome of their discussions in April.

The last time a Chinese leader visited Japan was former Premier Zhu Rongji in October 2000.

Both countries were competing for influence with ASEAN, which accelerated its target date for economic integration to 2015 and agreed to become a rules-based bloc with teeth, a bold departure for an organisation frequently derided as a talking shop.

ATOMIC ARSENAL

The Philippines, which holds ASEAN's rotating chairmanship, raised the spectre of a regional nuclear arms race in talks about Pyongyang's nuclear ambitions, which have encouraged Tokyo to start a debate on whether to drop its own ban on developing an atomic arsenal.

"It may be tempting for Japan to consider becoming a nuclear weapon state, particularly after the nuclear test by DPRK (North Korea) last 9 October," Philippine President Gloria Macapagal Arroyo told Abe.

"But the possession of nuclear weapons by more countries in our region will only lead to greater risks, not less. North Korea's nuclear weapons programme therefore cannot be allowed to stand."

Bedecked in pearls and a cream, floor-length Filipino gown, Arroyo hosted a gala dinner for the 16 Asian leaders on Sunday night.

Beauty queens and a Broadway star entertained the VIPs, who wore traditional Barong shirts made of pineapple fibres and were fed lobster and seafood salad served on black mother-of-pearl shells.

Abe, fresh from a tour of Europe where he pitched a more assertive diplomatic stance, highlighted Tokyo's desire to play a more prominent security role in the region with an agreement to support Southeast Asian maritime security.

Wen sealed a trade pact with ASEAN and said both sides would continue to advance their "strategic partnership" this year with discussions on a possible code of conduct for the South China Sea, a regional flashpoint due to competing territorial claims.

A wider meeting, including the heads of India, Australia and New Zealand will be held on Monday, when the 16 leaders aim to sign an energy security pact that will examine the possibility of a regional fuel stockpile.

ASEAN groups Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam -- countries that span the political and economic spectrum.