Japan's Prime Minister Shigeru Ishiba will meet President Donald Trump on a visit to the United States this week, top government spokesman Yoshimasa Hayashi said on Tuesday.

"If circumstances permit, he will visit the United States from 6-8 February and hold (his) first face-to-face Japan-US summit meeting with President Trump in Washington DC," Hayashi said.

"Through this visit we hope to build a strong relationship of trust with the new US administration and take the US-Japan alliance to new heights," he added.

The Nikkei business daily reported that Ishiba wants to discuss increasing imports of US shale gas with Trump — chiming with the president's pledge to "drill, baby, drill."

Ishiba is also expected to discuss a bid by Nippon Steel to buy US Steel blocked by previous president Joe Biden, according to public broadcaster NHK.

Citing national security concerns, Biden blocked Nippon Steel's $14.9 billion acquisition of US Steel last month, a highly unusual move that irked officials in Tokyo.

Ishiba intends to ask Trump to visit Japan at the earliest opportunity, local media reported.

Ishiba held a brief telephone call in November with then-president-elect Trump, and had reportedly unsuccessfully sought to meet with him before his inauguration in January.

However, Trump in December hosted Akie Abe — the widow of Japan's assassinated former prime minister Shinzo Abe — for a private dinner with Melania Trump at their Florida residence.

Last week, Ishiba stressed the importance of close ties with the United States for regional stability.

"As the balance of power in the region undergoes a historic change, we must deepen Japan-US cooperation further, in a concrete manner," Ishiba told parliament.

Tokyo must also "continue to secure the US commitment to the region, to avoid a power vacuum leading to regional instability," he added in a policy speech.

His comments underscored jitters over China's military build-up in the Asia-Pacific and Trump's "America First" policies, which may include demanding that allies such as Japan shoulder a larger proportion of defence costs.

Japan and the US are key defence allies and each other's top foreign investors.

Also in December — ahead of Ishiba — Masayoshi Son, head of Japanese tech investor SoftBank, stood beside Trump to announce a $100 billion investment in the United States.

Son also attended Trump's inauguration, followed by an announcement that SoftBank would lead a $500 billion project called Stargate to build AI infrastructure in the United States along with cloud giant Oracle and ChatGPT-maker OpenAI.

Then on Monday evening, Son and OpenAI chief Sam Altman met Ishiba, and discussed extending "Stargate into Japan," Son told reporters afterwards.

"We want to create the cutting-edge AI infrastructure — what I mean by that is the world's biggest, cutting-edge AI data centres," Son said, without giving further details.