The commission of eight experts told the UN Security Council yesterday that it reached this conclusion on the basis of recent inspections and seizures of banned cargo.
The council has adopted resolutions calling for increasingly tough sanctions aimed at thwarting Pyongyang's financial and technical ability to build weapons of mass destruction.
This came after a series of nuclear and long-range ballistic missile tests by North Korea over the past decade.
The new report posted on the UN website yesterday said North Korea has continued to defy those sanctions - by pushing ahead with its nuclear and ballistic missile programs and engaging in illegal arms trade.
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"It is experienced in actions it takes to evade sanctions. From the incidents analysed in the period under review, the Panel has found that it makes increasing use of multiple and tiered circumvention techniques," it added.
The panel said the case of the North Korean cargo ship Chong Chon Gang provided key insight into some of those techniques.
The ship was stopped by the Panamanian authorities in July 2013 carrying undeclared weapons that had been hidden under 10,000 tons of sugar from Cuba.
An investigation showed that the North Korean crew had used secret codes in communications.
The North Korean embassies in Cuba and Singapore are suspected of helping to arrange the arms shipment, the panel said.
Cuba has said that it was sending obsolete Soviet-era weapons to be repaired in North Korea.
This case helped confirm that one of North Korea's best sources of revenue was weapons exports, and technical support to manufacture and refurbish arms produced in the Soviet Union in the 1960s and 1970s, the panel said.