North Korea and trade talks will top US President Donald Trump's agenda on his marathon tour of the region, as Air Force One whisks him between five countries in 12 days.

A crammed itinerary will see the president attend summits with communist bosses, a reception at Japan's imperial court and -- of course -- play nine holes of golf.

But his personal rapport with a rotating cast of the region's leaders is likely to determine the success or failure of his trip, with global repercussions.

Trump enjoys a friendly relationship with Japan's Shinzo Abe, and a frosty start to dealings with Xi Jinping has blossomed into a near-bromance with the Chinese leader praised as "powerful" and "pretty terrific."

Trump gestures to Japan's Prime Minister Shinzo Abe as they play golf at the Kasumigaseki Country Club in Kawagoe, north of Tokyo, Japan. Photo: AFP, Reuters

But an uncertain welcome lies in store in South Korea -- which Trump has accused of appeasing a certain "Rocket Man" to the North -- and the Philippines, where any mention of human rights is liable to send President Rodrigo Duterte further into the arms of Beijing.

Trump ramped up his tough rhetoric against North Korea when he arrived in Japan yesterday, saying the United States and its allies are prepared to defend freedom and "no dictator" should underestimate US resolve.

In Seoul, Trump is scheduled to address South Korea's parliament, raising concerns he could go off script and send tensions with the nuclear-armed North spiralling with an impromptu remark.

Before his tour, Trump's national security adviser, Lt Gen HR McMaster, indicated that Trump plans to discuss with Japanese and South Korean leaders how to respond to the North Korea issue, including a possible scenario in which the nuclear crisis escalates into a military conflict.

McMaster spoke with Yomiuri Shimbun reporters and other journalists from countries Trump will visit on his first Asia tour.

The leaders pose after they signed hats reading 'Donald and Shinzo, Make Alliance Even Greater' after the game. Photo: AFP, Reuters

McMaster however emphasised that Trump "will consult with leaders across the region to understand better what more we can do to resolve this crisis short of war, which obviously everyone wants to avoid." He added that "all of us are running out of time."

US is also considering relisting North Korea as a state sponsor of terrorism, he said in an interview to The Korea Herald.

China is preparing to greet Donald Trump with what Ambassador to the US Cui Tiankai described as a "state-visit plus," with an extra dose of pomp and circumstance for the billionaire real estate developer.

Beijing is expected to roll out a military honour guard, formal banquet, and billions of dollars of trade deals.

David Dollar, an expert on China's economy at Brookings, predicted Xi will grant Trump a lavish welcome but few concessions.

Trump will travel to Danang city in central Vietnam on Nov 10 for the Asia-Pacific Economic Cooperation (Apec) economic leaders' meeting, reported The strait Times.

The next day, he will fly north to Hanoi for bilateral meetings with President Tran Dai Quang and other senior Vietnamese leaders. The fact that Trump was travelling to the Vietnamese capital for this meeting was important in itself, analysts said.

The communist country had stood to make one of the biggest gains from the 12-member Trans-Pacific Partnership (TPP) trade pact, which Trump pulled the US out of shortly after assuming presidency in January.

Hanoi has been open about its intention to try to salvage some of the potential economic gains from the TPP, but is not expecting any major deals with the US in the near term.

In the Philippines, where Trump will take part in a summit of Southeast Asian leaders, the US president's signals on Duterte's controversial crackdown on drugs will be closely watched.