U.S. President Joe Biden's visit to Japan this month is expected to coincide with the formal launch of a new U.S. economic strategy for the Indo-Pacific, even as China seeks "very aggressively" to fill a void since Washington quit a regional trade pact, Tokyo's ambassador to the United States said on Monday.

Ambassador Koji Tomita told an event hosted by Washington's Center for Strategic and International Studies that Japan and the United States had been working on the details of the Indo-Pacific Economic Framework (IPEF), which he said needed to strike a balance between inclusivity and high standards.

Asian countries are keen to boost ties with the United States, but have been frustrated by its delay in detailing plans for economic engagement with the region since former President Donald Trump quit a regional trade pact in 2017.