North Korea's past action should not be used to try to predict its future behaviour, the special national security adviser to South Korean President Moon Jae-in said in Tokyo on Monday, during a panel discussion on North Korea.

Moon Chung-in's comment came a day before a high-stakes summit meeting in Singapore between U.S. President Donald Trump and North Korean leader Kim Jong Un.

Talks between the leaders are expected to centre on ending the North's nuclear weapons and missile programmes in return for diplomatic and economic incentives.

Moon said the United States had blamed North Korea for breaking promises regarding its nuclear programme in the past, but that it "would have different views".

"Now is the time to set aside all those things. Let us see whether North Korea can deliver what the U.S. wants and the entire world wants," Moon said.

"Therefore past behaviour should not be the yardstick to judge current or future behaviour of North Korea."