Norway's 87-year-old ailing King Harald will have a permanent pacemaker implanted in a procedure on Tuesday in Oslo, the royal palace announced.

Europe's oldest reigning monarch, King Harald had to be repatriated to Norway on a medical transport flight on 3 March after contracting an infection while on holiday on the Malaysian island of Langkawi.

Upon his return, he was hospitalised at Oslo University Hospital, and the palace said at the time he would receive a permanent pacemaker to replace the temporary one he received while in Malaysia.

"His Majesty The King will this morning have a permanent pacemaker implanted," the palace said on Tuesday.

"After this, His Majesty will remain at the hospital for a few days."

Harald needs crutches to get around and has suffered a series of health issues in recent years, but has dismissed speculation that he would follow the lead of his 83-year-old distant cousin Queen Margrethe II in Denmark and abdicate. 

Crown Prince Haakon, 50, has stepped in as regent in the king's absence.