North Korea has shipped supplies to the Syrian government that could be used to make chemical weapons, United Nations investigators have revealed.

The disclosure, in a confidential 200-page long report seen by the New York Times, comes as the US and other countries have accused Syria of using chemical weapons on its own civilians, including a suspected chlorine gas attack in Eastern Ghouta in the past few days.

The report indicates there have been major flaws in international efforts to isolate both countries, and the new evidence could dampen efforts to bring North Korea to the negotiating table following a diplomatic détente at the South Korean Winter Olympics.

The items provided by North Korea reportedly included acid-resistant tiles, valves and thermometers. Investigators also detailed sightings of North Korean technicians working at chemical weapons and missile facilities inside Syria.

The report appears to confirm long-standing fears that Pyongyang may be funding its own weapons of mass destruction programme by trading its technological expertise with third parties.

It also supports suspicions since the start of the Syrian civil war in 2011 that President Bashar al-Assad has been assisted by the North Korean regime.