The leader of South Korean boyband BTS, RM, said diversity without borders was the source of creativity behind the group's worldwide success, as Asia-Pacific leaders gathered in his home country for a trade forum overshadowed by protectionist worries.

"I am just an artist. I am not a business leader, so today, I want to speak to you as a creator and an artist," said RM, a 31-year-old rapper, as he addressed a business event held on the sidelines of the annual summit of the Asia-Pacific Economic Cooperation grouping.

"When cultural barriers come down and different voices harmonise together, there's an explosion of creative energy," he said.

"This is why K-Pop is loved everywhere," he said, adding the group's ARMY global fan club spanning millions of loyal followers is "crossing borders and breaking down barriers through the pure power of cultural solidarity".

BTS has been reunited with all of its seven members having completed their mandatory military service this year and is now preparing for a big return with a new album next year ahead of a world tour.

RM, in his speech on Korean soft power, compared culture to a river flowing freely, and K-Pop to 'bibimbap', a traditional Korean dish of various ingredients mixed with rice.

Earlier in the day, the forum was addressed by U.S. President Donald Trump and South Korean President Lee Jae Myung, who then met nearby for tariff talks.

South Korea is betting on cultural exports to support its economy at a time when traditional manufacturers face growing protectionist barriers. President Lee has pledged support for the K-Pop industry to make his nation a global cultural powerhouse.

"K-Pop's shiny success is proof that cultural diversity and creativity are the greatest human potential. Of course, no borders, no limitations," RM said.