Geneva: United Nations refugee agency chief Filippo Grandi has voiced concern at the publication of a National Register of Citizens in India's northeast state of Assam that could leave some 1.9 million people in danger of becoming stateless.

"I appeal to India to ensure that no one is rendered stateless by this action, including by ensuring adequate access to information, legal aid, and legal recourse in accordance with the highest standards of due process," he said.

Although the nationality status of the approximately 1.9 million poeple left off the National Register of Citizens is not known, many are at risk of statelessness if they do not have another nationality, the UNHCR warned.

"Any process that could leave large numbers of people without a nationality would be an enormous blow to global efforts to eradicate statelessness," Grandi warned in his reaction late on Sunday.

UNHCR also urged the government to take action over any similar processes that could occur in other Indian states and urged authorities not to deport anyone whose nationality had not been verified.

The UN agency also repeated its offer to help the Indian government determinine people's nationality and prevent statelessness "in accordance with its mandate and international standards".