JAKARTA: Southeast Asian neighbours of conflict-riven Myanmar must consider imposing measures to hold its military rulers accountable, a United Nations expert said on Wednesday, adding the bloc is "deadlocked" over how to resolve the ongoing crisis.

United Nations Special Rapporteur on the human rights situation in Myanmar, Thomas Andrews, said the Association of Southeast Asian Nations (ASEAN) must not engage with Myanmar's military leaders as there had been no progress in implementing a five-point peace plan agreed between the bloc and the junta after it seized power in a 2021 coup.

"It is time to consider alternative options to break what has become a deadly stalemate," he said at a press conference in Jakarta. "ASEAN must consider measures to impose accountability on the junta for its grave human rights violations and blatant disregard for implementation of the Five-Point Consensus."

The peace plan calls for an immediate halt in hostilities, safe humanitarian access, and inclusive dialogue to achieve peace in the strife-torn country.

In November, an ASEAN leaders' summit issued a warning to Myanmar's junta and concluded a need for "concrete, practical and measurable indicators with a specific timeline." But frustration has grown over a lack of progress and the junta's stepped-up attacks on opponents.

Andrews' remarks come as Thai media reported the U.S. plans to slap fresh sanctions on state-owned Myanmar banks and on the heels of this week's Thai-hosted gathering of regional diplomats aimed at re-engaging junta leaders, who have been barred from high-level ASEAN meetings.

The Thai meeting was shunned by key ASEAN countries, including chair Indonesia, which has led behind-the-scenes efforts to bring the military and its opponents together for dialogue.

Andrews said the meeting in Thailand "can have the dangerous effect of legitimising the junta and undermining ASEAN unity".