The 87-year-old had been hospitalised while on a private trip in the resort island of Langkawi.

The plane took off from Langkawi airport shortly after 6 a.m. Oslo time (0500 GMT), daily Aftenposten and broadcaster NRK reported.

On Saturday, the Norwegian royal household had said the king might fly home in a couple of days and that the government had asked Norway's military to assist with the travel.

(Reporting by Gwladys Fouche in Oslo; Editing by William Mallard)