Nearly two dozen Asia-Pacific leaders hosted by US President Barack Obama gathered Saturday for the APEC summit, buoyed by Japan\'s decision to enter talks on a deal that could revamp US-Asia trade. US plans to reorient on Asia after a punishing decade pursuing wars in Iraq and Afghanistan received a fillip on the eve of the summit when Japanese Prime Minister Yoshihiko Noda joined trade negotiations on Friday. He was due to meet with Obama later Saturday. The Trans-Pacific Partnership (TPP), signed in 2005 as an obscure arrangement between just four members -- Brunei, Chile, New Zealand and Singapore -- has suddenly become the cornerstone of a US free trade drive. The entrance of Japan, the world\'s third-largest economy, into the talks was seen as imperative if the TPP is to be transformed into a meaningful pact that will knock down trade barriers across the Pacific. \"The Trans-Pacific Partnership ministers expect that the leaders of the TPP countries will be able to announce the broad outlines of a high-standard, ambitious, 21st-century trade pact,\" US Trade Representative Ron Kirk said. \"Of course, many of us believe that TPP can be the basis for a long-term APEC goal: a Free Trade Area of the Asia-Pacific,\" he told reporters after meeting trade and finance ministers ahead of Sunday\'s leaders\' summit. Experts warned that entry into the negotiations by Japan, which has strong protections for its farming industry, would complicate a process that could now drag on for years. \"To join the negotiations, Japan must be prepared to meet the TPP\'s high standards for liberalizing trade and to address specific issues of concern to the United States regarding barriers to agriculture, services and manufacturing trade, including non-tariff measures,\" Kirk said. The elephant in the room is China, the world\'s second-largest economy, which risks being left out in the cold if the trade zone takes off. Beijing has criticized the US ambitions as beyond the reach of developing economies in the fast-growing region. Ten nations are now in talks for an expanded Trans-Pacific Partnership: Australia, Brunei, Chile, Japan, Malaysia, New Zealand, Peru, Singapore, the United States and Vietnam. The vision is for an initial group of economies to form the core of the grouping. Membership will remain open, with more economies added after they agree to the same commitments as existing members. Several other countries in the Asia-Pacific Economic Cooperation forum, including Canada and Indonesia, have said they may join the TPP. Even China said it was considering it, although the United States is insisting on tough conditions that may preclude Beijing\'s entry. The implications for a trans-Pacific FTA are enormous, especially with the Doha Round of global trade talks still in limbo. The 10 countries already involved in negotiations account for more than a third of global output. In Honolulu there was a tight security blanket around the hotel where Obama and wife Michelle were staying. Part of the beach was closed off from other guests by a large metal fence shielding the view, and four police on jet skis with flashing blue lights patrolled the sea access where a large US Coast Guard vessel was moored. An orange boom cut across the bay to further protect the area reserved for Hawaii\'s most famous son. Obama hosts the APEC summit at the start of a nine-day Pacific tour that seeks to leave the economic gloom of America and Europe behind and look towards a region that is vital to future US prosperity. \"We obviously believe that the world\'s strategic and economic center of gravity will be the Asia-Pacific for the 21st century,\" Secretary of State Hillary Clinton said after talks with senior APEC officials. White House aide Ben Rhodes said Obama will deliver the message that \"the United States will continue to play the role it has throughout the last half century in being an anchor of security and stability in the region.\" After leaving Hawaii Monday, Obama will celebrate 60 years of security ties with Australia and make the first visit by a US president to the East Asia Summit, set for Bali next week. Thai Prime Minister Yingluck Shinawatra postponed what would have been her debut on the world stage at APEC to deal with the kingdom\'s worst floods in half a century, while Mexican President Felipe Calderon canceled after his interior minister died in a helicopter crash.