Finance Minister Taro Aso on Thursday urged the Group of 20 major economies to renew their commitment to sustaining the international order based on cooperation and openness that has come under threat from protectionism.

Speaking at a G-20 meeting of deputy finance ministers and deputy central bank governors to kick off the process of financial leaders' meetings under Japan's chair, Aso warned that protectionism and unfair trade practices would undermine economic stability.

The global recovery seen in the past several years is losing steam, with clear downside risks and heightened financial vulnerabilities at a time when support for the international order based on cooperation and openness is strained, Aso said.

"Dissatisfaction with economic inequality is growing. There is a serious risk that we will revert to a closed and fragmented world," Aso said in opening remarks at the G-20 gathering of deputy financial leaders.

"Protectionism and unfair trade practices lead to instability and perverse economic outcomes. We must renew our commitment to international cooperation and openness."

Rejection of protectionism, competitive devaluation and economic blockades has become the backbone of the G-20, he added.

Japan wants to focus on issues ranging from global trade imbalances to the impact of aging populations on the agenda when it chairs this year's G-20 financial leaders meetings.

Global imbalances had once been a key topic at G-20 meetings with a focus on each country's current account balance, or the overall flow of money including, but not confined to, trade.

This approach runs counter to U.S. President Donald Trump's focus on narrowing the U.S. trade deficit using import tariffs and bilateral deals. His "America First" policies and the U.S.-China trade war have overshadowed debates at recent G-20 meetings.

Japan will host a G-20 financial chiefs' meeting in Fukuoka in western Japan on June 8-9, followed by a leaders' summit in Osaka on June 28-29.