The Conflict Awareness Project said that when it came to regulating arms brokers the draft treaty was "so weak and watered down it will give comfort to illicit gun runners."
"The feeble treaty language means business as usual for traffickers who are filling the arsenals of the world's worst human rights abusers," said Kathi Lynn Austin of the Conflict Awareness Project.
The negotiations on the treaty in New York were delayed for the first week by a dispute over Palestinian participation, which was eventually resolved by allowing the delegation to sit at the front of the negotiating hall but without the right to participate as states with voting rights.
Such procedural bickering was typical of the arms trade talks, diplomats say, as countries that would prefer not to have a strong treaty tried to prevent the negotiations from moving forward. In February, preparatory talks on the rules nearly collapsed due to procedural wrangling and other disagreements.
One of the reasons this month's negotiations are taking place is that the United States, the world's biggest arms trader accounting for over 40 percent of global conventional arms transfers, reversed U.S. policy on the issue after Barack Obama became president and decided in 2009 to support a treaty.
But U.S. officials say Washington insisted in February on having the ability to veto a weak treaty.
"We have been making clear throughout our red lines (limits), including that we will not accept any treaty that infringes on Americans' Second Amendment rights," a U.S. official who did not want to be identified said on Tuesday, referring to U.S. domestic rights to bear arms -- a sensitive issue in the United States.
The other five top arms suppliers are Britain, China, France, Germany and Russia.
(Reporting by Michelle Nichols; Editing by Cynthia Osterman)