Russia on Thursday blocked the renewal of a panel of UN experts monitoring international sanctions on North Korea, weeks after the body said it was investigating reports of arms transfers between Moscow and Pyongyang.

North Korea has been under mounting sanctions since 2006 put in place by the UN Security Council in response to its nuclear programme.

Since 2019, Russia and China have tried to convince the Security Council to ease the sanctions, which currently have no expiration date.

Moscow's veto at the Security Council does not end the sanctions but blocked the body from renewing the annual mandate for a panel of experts who monitor the sanctions' implementation – and myriad alleged violations.

Russia's UN envoy Vasily Nebenzia said that without an annual review guaranteed to assess and potentially modify the sanctions, the panel of experts was unjustified.

"The panel has continued to focus on trivial matters that are not commensurate with the problems facing the peninsula," Nebenzia said.

"Russia has called for the council to adopt a decision to hold an open and honest review of the Council sanctions... on an annual basis."

Additional Security Council sanctions were levelled on Pyongyang in 2016 and 2017, but the North's sanctioned nuclear and weapons development have continued.

Last week, Pyongyang tested a solid-fuel engine for a "new-type intermediate-range hypersonic missile," state media reported.

Meanwhile, recent cruise missile launches have prompted speculation that North Korea is testing those weapons before shipping them to Moscow for use in Ukraine.

In its latest report, issued at the beginning of March, the sanctions panel reported that North Korea "continued to flout" sanctions, including by launching ballistic missiles and breaching oil import limits.

It added that it is investigating reports of arms shipments from Pyongyang to Russia for use in Ukraine.

"This veto does not demonstrate any concern for North Korean people or for the efficacy of sanctions," said Britain's UN ambassador Barbara Woodward.

"It is about Russia, gaining the freedom to evade and breach sanctions in pursuit of weapons to be used against Ukraine."

In a joint statement, 10 Security Council members, including Britain, France and the United States, defended the sanction monitors' work.

"In the face of these repeated attempts to undermine international peace and security, the panel's work is more important now than ever before," it said. (AFP)