U.S. Republican presidential candidate Donald Trump's proposal to meet North Korean leader Kim Jong Un is a "kind of propaganda or advertisement" in his election race, a senior North Korean official said on Monday.

Trump, in a wide-ranging interview with Reuters in New York last week, said he is willing to talk to the North Korean leader to try to stop Pyongyang's nuclear program, proposing a major shift in U.S. policy toward the isolated nation.

"It is up to the decision of my Supreme Leader whether he decides to meet or not, but I think his (Trump's) idea or talk is nonsense," So Se Pyong, North Korea's ambassador to the United Nations in Geneva, said on return from Pyongyang after attending the first ruling party congress in 36 years.