A delegation including three Nobel Prize laureates has completed a weeklong visit to North Korea in an effort to promote scientific and educational exchange in the face of tightening United Nations sanctions on the country.

Medicine prize winner Richard Roberts, economics prize winner Finn Kydland and chemistry prize winner Aaron Ciechanover told reporters in Beijing on Saturday that they met with students and academics, visited universities and research institutes, and delivered a number of lectures.

Their visit came as North Korea's ruling Workers' Party was preparing to bestow its top title on leader Kim Jong Un, although the three said they had no contact with the country's top leadership.

Roberts said the fact that North Korea had extended the invitation to visit showed its desire for expanded exchanges.