After taking time to lay the groundwork amid pressure from lobby groups and lawmakers from rural constituencies, Prime Minister Shinzo Abe formally announced Friday that Japan will join the Trans-Pacific Partnership free-trade talks.

Abe's government also unveiled its estimate of the possible economic impacts of joining the trade initiative, showing Japan's participation would drive up its gross domestic product by 0.66 percent, or around ¥3.2 trillion, but that production in the farm, fishery and forestry sectors could decrease by ¥3 trillion annually if all tariffs are abolished unconditionally.

"The TPP is turning the Pacific Ocean into an inland sea and a huge economic zone," Abe told reporters at his office.