WASHINGTON - Japan's entry into the Trans- Pacific Partnership (TPP) will deliver significant economic benefits for the United States, said a senior US trade official on Wednesday.

The TPP Agreement will "serve as a tool to expand US exports, which is critical to our continued economic recovery and to the creation and retention of high-paying, high-quality jobs in the United States," wrote Acting US Trade Representative Demetrios Marantis in a letter to Congress.

The participation of Japan will further increase the economic significance of the agreement, noted Marantis.

With Japan's entry, TPP countries would account for nearly 40 percent of the global GDP and about one-third of all world trade, added the official.

The United States and Japan completed bilateral TPP consultations on April 12. Marantis' letter served as a notification to the US Congress, which triggered a 90-day consultation with the legislature on US negotiating objectives with Japan.

The TPP talks between the United States and Japan will address concerns in the automotive sector and many other non-tariff measures, on which the Obama administration needs to hear from Congress and stakeholders.

The TPP is a key part of the Obama administration's efforts to boost exports and further integrate the US economy with the fast- growing region.

Besides the United States, the current TPP countries also include Australia, Brunei Darussalam, Canada, Chile, Malaysia, Mexico, New Zealand, Peru, Singapore and Vietnam.