North Korea’s invitation to this month’s World Economic Forum meeting in Switzerland has been revoked, after Pyongyang carried out a fourth nuclear test in defiance of a United Nations ban.

The World Economic Forum (WEF) said on Wednesday that foreign minister Ri Su Yong would go to the resort town of Davos for the gathering of the world's business and political elite from January 20th-23rd, but later said he was no longer welcome.

There was no immediate reaction from North Korea, which last sent a delegation to the forum in 1998.

Philipp Roesler, a member of the WEF managing board, told a Geneva news conference the forum had invited the Democratic People’s Republic of Korea (DPRK) late last year because “there had been some convincing, encouraging signals out of the DPRK that there may be an opportunity for international global dialogue”.

“But we have all seen what has happened last week,” Mr Roesler said, referring to the nuclear explosion.

“We decided after the nuclear test that ... there will be no opportunity for an international global dialogue in the spirit of the World Economic Forum.

“Therefore we could not maintain our invitation to DPRK.”

South Korea warned North Korea on Wednesday that the United States and its allies were working on sanctions to inflict “bone-numbing pain” after the nuclear test, and called on China to do its part to rein in its isolated neighbour.

South Korea is sending a delegation to Davos which the WEF said would be led by Choi Kyung-hwan, who stepped down as South Korea’s finance minister on Tuesday in preparation to run in parliamentary elections in April.

- Reuters