Joining a U.S.-backed trans-Pacific free-trade agreement would push up Japan's real gross domestic product by ¥2.4 trillion to ¥3.2 trillion, or 0.48 to 0.65 percentage point, according to an estimate by the Cabinet Office released Wednesday.

In line with Prime Minister Naoto Kan's interest in joining the Trans-Pacific Partnership Agreement (TPP), as well as the nation's hosting of this year's Asia Pacific Economic Cooperation meetings next month, the government came up with several estimates of the economic impact of the FTA.

The trade ministry estimated that if Japan neither joins the TPP nor signs economic partnership agreements with the European Union and China, while South Korea inks free-trade agreements with the U.S., China and the EU, real GDP will decrease by about ¥10.5 trillion by 2020 with the loss of 812,000 jobs.