UN arms embargoes are systematically violated and need to be made tougher if they are to end conflict and curb human rights abuses, campaigners say.
Weapons continue to flow into many countries despite embargoes
Each of the 13 UN embargoes imposed in the past decade has been breached, the Control Arms Campaign has found.
The group, including Oxfam and Amnesty International, says unscrupulous arms dealers are "making a mockery" of UN attempts to tackle global conflict.
It is calling for states to agree an arms trade treaty.
It says such a treaty would enable governments to act more effectively to prevent arms falling into the wrong hands.
Currently, although arms embargoes are legally binding under the UN charter, many member states have not ratified them into laws that would make violations a criminal offence.
Arms to Liberia
"Over the past 10 years, systematic violations of UN arms embargoes have met with almost no successful prosecutions," said Irene Khan of Amnesty International.
"Unscrupulous arms dealers continue to get away with grave human rights abuses and make a mockery of the UN Security Council's efforts."
Campaigners say that arms embargoes have only been used in eight of 57 conflicts between 1990 and 2001, including Ethiopia and Eritrea, Iraq and the former Yugoslavia.
Embargoes are currently in force in Ivory Coast, Liberia, Somalia, the Democratic Republic of Congo, Rwanda, Sierra Leone and Sudan.
But, in one incident in 2002, campaigners say, enough arms were flown from Europe into Liberia to kill the whole population and keep armed groups supplied for a whole year. No-one was ever prosecuted, despite a UN embargo being in place at the time.
In their 43-page report, the group says that UN teams responsible for monitoring embargoes often have "woefully inadequate resources and time".
It says import and export documents are routinely faked and state officials often cover up arms transfers.
The Control Arms Campaign - which also includes the International Action Network on Small Arms - plans to use the next 100 days leading up to a UN conference on small arms, to lobby members of the Security Council to support an international arms trade treaty.