A wreath was on Sunday morning lain in Oslo and at 11am services will be held in Oslo cathedral and in Hole church, near Utøya. Further memorial services will be held on Utøya later in the day.
A memorial concert is scheduled for this evening on Rådhusplassen in central Oslo.
Memorial services will also be held in Stockholm and Gothenburg and a three minute silence will be observed on Sergels Torg in central Stockholm at 3.25pm. The time marks exactly one year after the bomb exploded in Oslo's government district.
Furthermore the Eskil Pedersen, the chair of The Workers' Youth League - the youth wing of Norway's Labour party which was targeted in the shootings, will be the host for Sveriges Radio's popular "Summer" radio programme at 1pm.
"It is as incomprehensible today as it was then," he wrote.
"Our thoughts are with all the life that was extinguished all too soon, for the survivors and the terrible memories that follow them every day and to the families who were left in grief and loss."
Reinfledt concludes by saying that Norway's open and tolerant way of dealing with disaster "has strengthened everyone's belief in the democratic values of society".