The 83-year-old King Harald V of Norway was released from hospital on Monday after being admitted last week with respiratory problems, the palace said.
"The hospital is continuing its evaluation and the king will remain on sick leave until October 4," a statement said.The monarch, who has been on the throne for 29 years, was admitted to Oslo University Hospital on Friday morning.
While he was said to be suffering from a respiratory ailment, his condition was not related to the novel coronavirus, the palace said Friday.
Crown Prince Haakon has temporarily taken over his duties.
A keen yachtsman who has taken part in regattas including the 1964 Olympic Games in Tokyo, King Harald is seen by Norwegians as a unifying figure.
He has insisted he will not abdicate despite declining health that saw him spend a week in hospital in January after a bout of dizziness.
In the early 2000s, he underwent surgery for bladder cancer and later to repair a heart valve.