Finance chiefs gathered Thursday in Yokohama near Tokyo for the Asian Development Bank's annual meeting to promote regional cooperation amid concerns about protectionism and to discuss ways to achieve sustainable and inclusive economic growth.

Behind the 50th annual gathering of the ADB's board of governors and related events through Sunday looms the existence of a Chinese-led infrastructure investment bank whose clout is growing amid the need for huge infrastructure financing to support future growth in the Asia-Pacific region.

Delegates from the ADB's 67 member countries and regions are tasked with addressing concerns about inward-looking policies and geopolitical risks that could hurt economic activity.

"We are not competing" for the number of members, ADB President Takehiko Nakao told a press conference in the Japanese port city, adding that he does not see the Asian Infrastructure Investment Bank as a rival. "We can cooperate with the AIIB because they are focusing on infrastructure building."

Since its launch in 2015, the AIIB has gathered more members than the ADB to reach 70. Japan and the United States, the two leading financial contributors to the 50-year-old ADB, have not joined the Beijing-led initiative.

Regional cooperation is gaining renewed attention as this year marks the 20th anniversary of the Asian financial crisis in 1997 that sent the Thai baht and other currencies plunging and roiled local economies.

The Manila-based ADB projects the region's economies, excluding some advanced countries such as Japan, will grow 5.7 percent in 2017. But uncertainty remains over the economic and trade policies of U.S. President Donald Trump, Britain's exit from the European Union, and France's presidential election.

"At this moment, I don't think protectionism is affecting our growth projections," Nakao said. But he stressed the need to keep the momentum going for further opening of trade systems.

Through discussions over the course of the annual meeting, delegates are likely to assess potential risks to growth, and explore ways to bridge the gap in infrastructure building, prevent pandemics, and improve healthcare.

Established in 1966, the ADB has a long history of giving assistance to developing countries in building basic infrastructure. For the region to gather growth momentum, infrastructure needs more investment, which the ADB estimates will total $26 trillion between 2016 and 2030.

A series of multilateral meetings are scheduled to be held on the sidelines of the ADB event, which Japanese Finance Minister Taro Aso and Bank of Japan Governor Haruhiko Kuroda plan to attend.

On Friday, the finance chiefs of Japan, China, and South Korea are expected to exchange views on recent financial developments at a time of heightened regional tensions due to North Korea's repeated missile launches.

Finance ministers and central bankers from Japan and the Association of Southeast Asian Nations also plan to hold talks on the same day, with policy coordination in crisis situations high on the agenda.

The Chiang Mai initiative, a multilateral currency swap arrangement set up in the aftermath of the 1997 crisis is expected to be a major theme when ASEAN finance chiefs meet with their Japanese, Chinese, and South Korean counterparts.

Japan is hosting the annual event for the fifth time. The past four meetings were held in Tokyo, Osaka, Kyoto and Fukuoka.

Around 5,000 participants, including central bank governors, government officials and business leaders from the Asia-Pacific region, North America and Europe are expected to participate in the annual event in Yokohama.