Harald, who is 87, fell ill with an infection while on holiday in Malaysia and was admitted to hospital there last week. On Monday the king returned to his homeland on a special plane after a stopover in the United Arab Emirates.
According to Oslo officials, the king had already been fitted with a temporary pacemaker before the flight, which his personal physician said was to make the return journey safer for the monarch.
Harald is now in hospital in Oslo. He is said to be recovering from the infection, but his heart rate remains low, so a permanent pacemaker is therefore necessary.
The procedure will reportedly take place once the infection has completely cleared up.
Several members of the royal family visited the king in hospital on Monday, including Queen Sonja and Crown Prince Haakon. The king has initially taken two weeks' sick leave. In the meantime, Haakon will take over his father's official duties as regent.
--BERNAMA-dpa
