Four years after a right-wing extremist gunned down 69 people, Norway's idyllic island of Utoya is reopening to a flood of newcomers to the Labor Party's youth camp for the first time since the massacre in 2011.

Emilie Bersaas, a camp organizer, says they won't allow "that dark day (to) overshadow the nice and bright" memories of camps there.

More than 1,000 students have enrolled for the three-day weekend seminars on politics that open Friday. Private visitors a day earlier will include NATO Secretary-General Jens Stoltenberg, Norway's prime minister at the time of the massacre.

Self-styled "militant nationalist" Anders Behring Breivik walked through the island on a murderous rampage on July 22, 2011, after killing eight people with a car bomb at the government headquarters in the capital, Oslo.