• U.S. Secretary of State Antony Blinken's trip to Southeast Asia is significant as it sends a strong signal that Washington is keen to strengthen relations with the region at a time of growing tensions with China, according to an expert from a think tank.
• Simon Tay, chairman of Singapore Institute of International Affairs, said Blinken's swing through the region this week "must be seen clearly in the context of the Sino-American competition."
• Blinken also criticized China's aggression in the South China Sea, noting it threatened more than $3 trillion in annual trade and is a cause of growing concern.

U.S. Secretary of State Antony Blinken's trip to Southeast Asia is significant as it sends a strong signal that Washington is keen to strengthen relations with the region at a time of growing tensions with China, according to an expert from a think tank.

Simon Tay, chairman of the Singapore Institute of International Affairs, said Blinken's swing through the region this week "must be seen clearly in the context of the Sino-American competition."

"The interesting part to me is that there is a kind of silver lining for these countries and for ASEAN as a whole, provided this competition does not tip over into actual conflict and a Cold War mentality," he told CNBC's "Street Signs Asia." 

"It's a big signal that he is coming to the region and starting with Indonesia," he added. 

This is Blinken's first visit to Southeast Asia since President Joe Biden took office in January. In his first stop in Indonesia on Tuesday, the top diplomat called on U.S. allies and partners in the region to defend the rules-based order.

"Let me be clear: the goal of defending the rules-based order is not to keep any country down. Rather, it's to protect the right of all countries to choose their own path, free from coercion and intimidation, " said Blinken, who will also visit Malaysia and Thailand this week.

"It's not about a contest between a U.S.-centric region or a China-centric region – the Indo-Pacific is its own region," he added.

The Secretary of State also criticized China's aggression in the South China Sea, noting it threatened more than $3 trillion in annual trade and is a cause of growing concern.

"That's why there is so much concern – from Northeast Asia to Southeast Asia and from the Mekong River to the Pacific Islands – about Beijing's aggressive actions," he added.

China has been increasingly agitated by the Biden administration's Indo-Pacific strategy. Part of that priority is the shoring up of an informal strategic alliance between the United States, Japan, India and Australia, known as the Quadrilateral Security Dialogue or Quad.

Ashley Townshend, director of foreign policy and defense at the United States Studies Centre at the University of Sydney, underlined that Blinken's visit is critical because the Biden administration is in the early stages of rolling out a comprehensive Indo-Pacific economic framework.

"Which really tries to go to one of the core demands of Southeast Asian countries from the United States, which is to see the United States invest and invest more substantially in the region," he said as well as "bolstering a more resilient region ... that is more able to stand up to Chinese coercion."