Austin is in Tokyo on a brief trip for bilateral talks before heading to the Shangri-La Dialogue defence summit in Singapore.

Speaking before talks with his Japanese counterpart, Austin said the alliance faced "common challenges from the PRC's (China's) coercive behaviour, North Korea's dangerous provocations and Russia's cruel war of choice in Ukraine."

"But we are united by our shared interests and shared values. And we are taking important steps to modernise our alliances and strengthen our deterrence," he added.

Austin cited trilateral cooperation with Australia and South Korea as well as the expanded "pace, scope and scale" of exercises and training.

US and Japanese forces are becoming "more versatile, resilient, and mobile," he added, praising Japan's decision to obtain counterstrike capacity and improve information-sharing with Washington.

Austin arrived in Japan on Wednesday, hours after North Korea made a failed attempt to launch a spy satellite using technology banned under UN resolutions.

Pyongyang has stepped up missile launches in the past year, and Tokyo is also contending with growing pressure from Chinese vessels around islands contested with Beijing.

Last year, Tokyo unveiled a major defence overhaul, pledging to boost security spending to two percent of GDP by 2027 and calling China the "greatest strategic challenge ever" for Japan.