Its armed wing, the Mon National Liberation Army (MNLA), has fought the government of Myanmar since 1949, but under different names.

The NMSP has attempted many times unsuccessfully to push for constitutional and political reforms through the government sponsored National Convention.

On 11 May 2023, the NMSP withdrew Peace Process Steering Team, which consists of ethnic armies that signed the Nationwide Ceasefire Agreement.

[5] On 23 May 2022, members of the NMSP held a meeting with the military ruler of Myanmar, Min Aung Hlaing, over the possibility of a separate constitution for Mon State.

[6] Despite previous negotiations, in February 2024, a splinter group of the New Mon State Party and its armed-wing Mon National Liberation Army called the New Mon State Party (Anti-Military Dictatorship), made up of several senior NMSP officials, announced that they will no longer negotiate with the junta and will be joining hands with the revolutionary forces, effectively declaring war on the junta.