Florida Governor Ron DeSantis praised Japan's push to bolster its defences as he kicked off an international tour in Tokyo on Monday before a possible presidential run.

The Republican is widely expected to seek the US presidential nomination next year, and his trip to Japan, South Korea, Israel and Britain is seen as a bid to burnish his diplomatic and security credentials.

"We very much applaud your efforts to bolster your defences," DeSantis told Prime Minister Fumio Kishida before talks, referring to Tokyo's decision to overhaul security strategy and boost defence spending.

"We really believe that a strong Japan is good for America and a strong America is good for Japan. So we commend you on that, and we hope that our country is there with you every step of the way."

The tour is officially billed as an effort to build business opportunities for Florida, and DeSantis touted his state's economic appeal.

"We've noticed we're the biggest market in the United States that doesn't have a direct flight to Japan," he told Kishida, saying he hoped to meet with airlines to "try to do something about it".

Japan relies on Washington for defence, and its leaders will be watching next year's presidential race closely, eager to ensure ties remain strong regardless of who enters the White House.

Kishida told DeSantis, who is travelling with his wife, that he hoped the visit would help "deepen the understanding of Japanese politics, economy and culture".

The Florida governor played to his audience by congratulating Kishida on the country's victory in last month's World Baseball Classic, led by national hero Shohei Ohtani.

"I wish we had Ohtani, but that's just the way things go," the governor said.

DeSantis will have a working dinner later on Monday with Japan's Foreign Minister Yoshimasa Hayashi, before continuing on to Seoul. (AFP)