Japan formally joined negotiations for a US-led trans-Pacific agreement on Tuesday, raising hopes for a free trade deal which would cover nearly 40 percent of the global economy. Delegations from Asia-Pacific countries, Latin America and the US have been meeting in Kota Kinabalu, the capital of Malaysia\'s eastern Sabah state, since July 15 to push ahead with the Trans-Pacific Partnership (TPP). Japan, which had been observing the talks from the sidelines, only made a commitment to enter negotiations after Japanese Prime Minister Shinzo Abe came to power in December. The Japanese delegation joined the 18th round of talks on Tuesday, an official involved in the discussions told AFP, declining to comment further. In Tokyo Japanese Chief Cabinet Secretary Yoshihide Suga said free trade was \"a pillar of our country\'s diplomatic policies\". \"By firmly protecting what we have to protect and by pressing what we should press, we will pursue the best results and contribute to our national interest,\" he told reporters. Japan has faced resistance from a powerful lobby of superannuated farmers tending tiny plots who are concerned about the extra competition the TPP would bring. But after Abe\'s Liberal Democratic Party won a thumping victory in upper house elections on Sunday, gaining control over both legislative chambers, the government vowed it would press ahead with reforms. The Japanese premier will be in Malaysia on Thursday before a planned meeting in Singapore Friday with US Vice President Joe Biden. The TPP is a key plank of US president Barack Obama\'s \"pivot to Asia\" and, while Washington denies the charge, is seen as part of an effort to contain China -- which has never been given an invite to the party. Biden has said he aims for the completion of the deal this year. Gundy Cahyadi, an economist with OCBC Bank Singapore, said powerhouse Japan\'s entry was a positive sign. \"The more open it is, the better it is for all the countries involved. It\'s a good signal that they (Japan) are willing to engage and be engaged,\" he said. Japan\'s market of 128 million consumers is a potentially big prize for foreign firms, many of which presently complain that Tokyo kicks up obstacles -- tariffs and non-tariff barriers -- that stop their products reaching shelves. The automotive, healthcare, insurance and agricultural sectors are seen as particularly cushioned. US automakers complain bitterly that they are never competing on a level playing field against their Japanese rivals. However some voices warn that Tokyo will try to write in so many exceptions that any agreement might fall far short of expectations, and could, in any case, take much longer to reach. Other than Japan, Australia, Brunei, Canada, Chile, Malaysia, Mexico, New Zealand, Peru, Singapore, the United States and Vietnam are party to talks for the free-trade deal. The TPP has also faced resistance in some of these nations. In Malaysia activists have staged several protests against the deal, fearing it will compromise the country\'s sovereignty and calling on the government to disclose details on the agreement. On Saturday police briefly detained 14 protesters in Kota Kinabalu.