A UN report has warned that "systematic abuses" by Somalia's government have allowed weapons to be diverted to warlords and al Shabab militants.
The report for the UN's sanctions committee calls for the restoration of an arms embargo on Somalia that was relaxed last year.
It said a key advisor to Somalia's president has been involved in planning weapons deliveries to militants.
Somalia's mission to the UN has questioned the report's validity.
The confidential 14-page report was compiled by the UN's Somalia and Eritrea Monitoring Group, a panel of independent experts supervising compliance with the sanctions regime.
It said the group had "identified a number of issues and concerns over current management of weapons and ammunition stockpiles" by Somalia's government.
These, it said, "point to high-level and systematic abuses in weapons and ammunition management and distribution".
The Security Council imposed the embargo on Somalia in 1992 as the country descended into two decades of unrest.