In a joint statement on Wednesday, the NGOs said that "no government should sell a single bullet to the junta."
Ousting the civil government of Aung San Suu Kyi in a coup on February 1, the military government has been ruling the country ever since.
Rebels Attack Two Military Bases in Myanmar
The organizations jointly asserted that "imposing a global arms embargo on Myanmar is the minimum necessary step the Security Council should take in response to the military's escalating violence."
The military said on February 1 that it had arrested Suu Kyi and her associates over accusations of voter fraud by her National League for Democracy (NLD) party in the November 2020 elections.
The military then placed commander-in-chief Min Aung Hlaing in power and promised to hold new elections in a year and transfer power to the winner.
The military takeover has triggered international condemnation and mass protests. One of them is the Assistance Association for Political Prisoners (AAPP), an advocacy group that says that security forces have killed nearly 770 people since the coup.
"Mere condemnation by the international community has had no effect," a senior UN Advocate for Amnesty International, Lawrence Moss, added.
"It is time for the UN Security Council to use its unique powers to impose a comprehensive global arms embargo in order to try and end the military's killing spree."
Louis Charbonneau, with Human Rights Watch, similarly said, "The council's occasional statements of concern in the face of the military's violent repression of largely peaceful protesters is the diplomatic equivalent of shrugging their shoulders and walking away."
On the other hand, China holds veto-wielding power on the Council, expressed opposition to any sanctions, and reaffirmed its support for a political solution to the crisis in Myanmar.
To those ends, China's envoy to the United Nations Zhang Jun said in a press conference Monday that there should be support for efforts by the Association of Southeast Asian Nations (ASEAN), to which Myanmar is a member, to find a solution.
The military-ruled Myanmar from 1962 until 2011, when Suu Kyi ended the junta rule. However, her international reputation was tarnished after she defended a military campaign of "genocide" against the minority Rohingya Muslim community in 2017.