Southeast Asian countries are considering a proposal to send a humanitarian aid mission to Myanmar as a potential first step in a long-term plan to broker a dialogue between the junta and its opponents, diplomats familiar with the discussions said.

The proposal is being considered ahead of a planned meeting of the Association of Southeast Asian Nations (Asean) leaders this month. Diplomats said it might be attended by Myanmar junta chief Min Aung Hlaing, who took power in a Feb 1 coup that has plunged his country into turmoil...