JAPAN and the US have agreed on a deal to allow Tokyo to join talks on a US-led Asia-Pacific free-trade pact that Japanese Prime Minister Shinzo Abe is making a keystone of his strategy to open Japan's economy and spur long-sought growth.

The agreement brings Japan closer to entering talks on the Trans-Pacific Partnership, which Japan hopes to participate in as early as July.

"Japan and the United States have reached an agreement on Japan's participation in the TPP talks," Abe said yesterday.

"I think Japan's national interests are protected under this US-Japan agreement," he said, adding that he hoped Japan could take part in the negotiations as soon as possible.

Abe last month announced his decision to join the trade talks - despite fierce opposition from Japan's politically powerful farm lobby - as part of a "third arrow" in his "Abenomics" policy triad, after fiscal spending and drastic monetary policy easing.

Japan needs formal approval by all 11 participating countries to take part in the talks. If Japan does join, the pact would cover an area that accounts for almost 40 percent of world economic output.

The US-Japan agreement allows the White House to give Congress 90-days' notice that it plans to start trade negotiations in time for Japan to participate in a July round of TPP talks.

US labor groups have been worried about the impact of removing US tariffs on autos.