"I will have frank discussions with incoming president Trump and lead the alliance to new heights," Shigeru Ishiba said in parliament in a key policy address.

"Naturally, the US has its own national interest and Japan has its own national interest. That is why I think exchanging opinions frankly and enhancing the national interests of both countries in a synergetic way will help realise a free and open Indo-Pacific," he said.

Beijing has displayed increasingly assertive behaviour in territorial disputes in the Asia-Pacific region, including around Taiwan.

Tokyo is also alarmed by nuclear-armed North Korea's expansion of its missile activities. Trump met North Korean leader Kim Jong Un in his first term.

Ishiba, a self-confessed defence "geek", has called for the creation of an Asian NATO with its principle of an attack on one being an attack on all.

"The Japan-US security alliance is the foundation of Japan's diplomacy and security," Ishiba said.

"At the same time, however, the United States receives great strategic benefits from the existence of facilities and areas (controlled by) US Forces in Japan," he said.

In Trump's first term, Japan's then-premier Shinzo Abe appeared to have warm personal relations with the US president, playing golf together several times.

Ishiba and the US president-elect had what the Japanese premier called a "very friendly" phone conversation after Trump's election win earlier this month.

Key allies Japan and the United States are each other's top foreign investors, and 54,000 US military personnel are stationed in Japan, mostly in Okinawa east of Taiwan.

Japan has been shedding its strict pacifist stance, moving to obtain "counterstrike" capabilities. US President Joe Biden and Ishiba's predecessor Fumio Kishida announced a "new era" in defence in April.

Japan is already in the process of doubling its military spending to the NATO standard of two percent of GDP.

But Trump's "America First" approach could mean that in his second term he could provide less cash and press Japan to do more.

- Tariffs -

Trump also caused panic among some of the biggest US trading partners on Monday when he said he would impose tariffs of 25 percent on Mexican and Canadian imports and 10 percent on goods from China.

Many Japanese exporters, including carmakers Toyota and Honda, have plants in Mexico and in Canada. Both firms' shares fell sharply this week.

Japanese government officials have declined to comment on Trump's tariff threats and Ishiba did not address the issue directly on Friday.

But Masakazu Tokura, chairman of Japan's most influential business organisation Keidanren, said on Tuesday that the impact on Japanese firms could be "enormous".

Trump could also press Japan to join expanded US efforts to limit exports to China like semiconductor equipment and AI chips, which could hurt Japanese firms.

- China -

While pointing out Beijing's increasing military activities, Ishiba on Friday signalled willingness to build "constructive" ties, pointing to recent moves such as easing visa rules.

He said he had "an engaged discussion" with Chinese President Xi Jinping on the sidelines of an APEC meeting in Peru this month.

"Between Japan and China, there are various concerns and differences of opinion," he said.

"We will assert what needs to be asserted. However, we will also cooperate with each other in areas where we can... China's stable development benefits the entire region."