US committed to Japan's defence: Biden

US President Joe Biden has told Japanese Prime Minister Fumio Kishida that the United States remained strongly committed to its alliance with Japan and praised Tokyo's "historic" defence reforms.

Kishida is in Washington on the last stop in a tour of the G7 industrial powers and has been seeking to bolster long-standing alliances amid rising concern in Japan, and the United States, about mounting regional security threats from China, North Korea and Russia.

In a meeting at the White House on Friday, Biden called it a "remarkable moment" in the US-Japan alliance and said the two nations had never been closer.

"Let me be crystal clear: the United States is fully, thoroughly, completely committed to the alliance, and importantly ... to the defence of Japan," he said, while also thanking Kishida for strong leadership in working closely on technology and economic issues.

"We are modernising our military alliances, building on Japan's historic increase in defence spending, and new national security strategy."

Kishida thanked Biden for US work on regional security and said: "Japan and the United States are currently facing the most challenging and complex security environment in recent history."

He said Tokyo had formulated its new defence strategy released last month "to ensure peace and prosperity in the region".

Kishida said he looked forward to a "candid" exchange of views on issues including "a free and open Indo-Pacific" - language the two sides use to describe efforts to push back against China - the G7, which Japan's chairs, and climate change.

Japan last month announced its biggest military build-up since World War II - a dramatic departure from seven decades of pacifism, largely fuelled by concerns about Chinese actions in the region.

"Biden commended Japan's bold leadership in fundamentally reinforcing its defence capabilities and strengthening diplomatic efforts," according to a joint US-Japan statement issued after the meeting.

US and Japanese foreign and defence ministers met on Wednesday and announced increased security co-operation following nearly two years of talks.

Japan's military reform plan will see it double defence spending to two per cent of GDP and procure missiles that can strike ships or land-based targets 1000 kilometres away.

Biden and Kishida were expected to discuss security issues and the global economy and their talks were likely to include control of semiconductor-related exports to China after Washington announced strict curbs last year, a senior US official said.