Top US diplomat Antony Blinken and Pentagon chief Lloyd Austin arrive in Tokyo Monday on their first overseas trip, looking to rally key Asian allies as a bulwark to China.

The pair, travelling separately, will meet in Japan for the first leg of their trip, holding talks with their counterparts as well as Prime Minister Yoshihide Suga.

They will both continue on to South Korea, before Defense Secretary Austin heads separately to India and Secretary of State Blinken holds talks back in the United States with Chinese officials.

President Joe Biden's team has been deliberately slow to start the usually hectic pace of diplomatic travel that marks a new administration, hoping to set an example discouraging travel during the pandemic.

But the administration has also made clear it wants to reset US relations with the rest of the world, particularly traditional allies, after the tumult of the Donald Trump era.

In a joint opinion piece in the Washington Post Monday, Austin and Blinken said they would be looking to "revitalise our ties with friends and partners".

The visit will also be about presenting a united front on the challenges posed by China.

"Our combined power makes us stronger when we must push back against China's aggression and threats," they wrote.

"Together, we will hold China accountable when it abuses human rights in Xinjiang and Tibet, systematically erodes autonomy in Hong Kong, undercuts democracy in Taiwan or asserts maritime claims in the South China Sea that violate international law. If we don't act decisively and lead, Beijing will."

Talks with Chinese officials

Speaking in Hawaii before heading to the region, Austin said he and Blinken would be "listening and learning".

Washington was seeking to enhance US military capacity with allies, he added, warning that the "competitive edge that we've had has eroded" as China rapidly modernises its army.

"We still maintain that edge. We are going to increase that edge going forward," he told reporters at the seat of the US military command for the Indo-Pacific region. "Our goal is to make sure that we have the capabilities and the operational plans... to be able to offer a credible deterrence to China or anybody else who would want to take on the US."

The pair arrive in Asia after an unprecedented summit of the leaders of the so-called "Quad" -- an informal alliance of the United States, Japan, India and Australia seen as a counterbalance to China's increasing influence.

Blinken's events in Tokyo and Seoul will be largely virtual, with addresses to Japanese business leaders and journalists by video conference, though his talks with officials will be in person.

In Seoul, he will consult on Biden's review of policy towards Pyongyang in the wake of Trump's summits with North Korean leader Kim Jong Un.

The Pentagon said Austin will meet Defense Minister Rajnath Singh in Delhi and seek a deepening partnership with India, whose relations with China have worsened following a deadly Himalayan clash last year.

Blinken will return from Seoul to the United States and join Biden's national security advisor Jake Sullivan for talks in Anchorage with their Chinese counterparts.

Blinken said last week he expected to "lay out in very frank terms many concerns that we have with Beijing's actions and behaviour".

Any future engagement would "really have to be based on the proposition that we're seeing tangible progress and tangible outcomes on the issues of concern to us with China", he told the House Foreign Affairs Committee.