"Noeleen Heyzer, Special Envoy of the Secretary-General on Myanmar, will conclude her assignment on 12 June," Stephane Dujarric said, without giving a reason for her departure.

The global body's Secretary-General Antonio Guterres "is thankful to Ms. Heyzer for her tireless efforts on behalf of peace and the people of Myanmar," the spokesman said, adding a new envoy would be appointed.

Heyzer, a Singaporean sociologist, was named as envoy by Guterres in 2021 and tasked with urging the Myanmar junta to launch political dialogue with its opponents.

She visited the Southeast Asian nation last August and met junta chief Min Aung Hlaing and other top military officials in a move criticised by rights groups.

But she was denied a meeting with detained democracy leader Aun San Suu Kyi and later irked junta officials who accused her of issuing a "one-sided statement" of what had been discussed.

Myanmar has been in turmoil since a 2021 coup that sparked renewed clashes with ethnic rebels and the formation of dozens of "People's Defence Forces" now battling the junta.