South Korea, Japan and the United States on Friday urged UN member states to repatriate North Korean workers, claiming they continued to help Pyongyang dodge sanctions and fund its weapons programmes.

North Korea was also engaged in "malicious cyber activities" that supported its military expansion, representatives of the three countries said in a joint statement.

Overseas workers have long been a significant source of income for nuclear-armed North Korea, but under a 2017 United Nations resolution, member states had until December 2019 to repatriate them.

But after a Friday meeting in Seoul, the South Korean, Japanese and US special envoys for North Korea stressed the need for countries to ensure compliance with UN Security Council (UNSC) sanctions.

"Overseas DPRK IT workers continue using forged identities and nationalities to evade UNSC sanctions and earn income abroad that funds the DPRK's unlawful weapon of mass destruction and ballistic missile programmes," the envoys said, using North Korea's official name.

"We are also deeply concerned about how the DPRK supports these programmes by stealing and laundering funds as well as gathering information through malicious cyber activities."

North Korea stole as much as US$1.7 billion in cryptocurrency last year alone, they added. (AFP)