Oslo: Norway's King Harald, 85, will remain in hospital "for a few days" following an infection but his condition is stable, the royal household said Monday.

The king was admitted to Oslo's university hospital for treatment with intravenous antibiotics, a statement said, adding: "His condition is stable".

Harald has suffered health problems recently, including Covid, knee surgery in 2021, respiratory problems and was hospitalised for another infection in August.

The king also underwent surgery in 2003 for bladder cancer and another operation in 2005 for heart valve problems.

The former Olympic yachtsman has refused to abdicate and even took part in the World Sailing Championships in late July.

He is the grandson of Haakon VII -- the first Norwegian regent after the country gained independence in 1905 -- and has ruled since January 1991.