Civil society leaders from 40 countries concluded a three-day gathering in Tokyo on Tuesday with calls that, amid violence and legal restrictions on them globally, such organizations' voices should not be excluded from the Group of 20 leaders' summit set to be hosted by Osaka this year.

"There are increased worries that the space for civil society to operate in is shrinking, especially in Asia," said Yuka Iwatsuki, the chair of Civil 20, one of several groups that advise G20 leaders on a broad range of international social and economic issues.

"The G20 governments must recognize that civil society organizations are indispensable and that a diversity of voices from civil society enriches policymaking," she added.