The PST -- the Norwegian Police Security Force, somewhat comparable to the British MI5 -- concluded in its most recent publicly available risk analysis, published in February, that right-wing extremists posed “no serious threat.”
Dayuhan, I am in no position to know what the right wing threat is in Norway, but I also don't think one madman (a condition that tends to manifest itself in every nation) constitutes a grave threat trend. If there are additional planned or actual attacks conducted by the far right indicating a conspiracy then the threat would be high in my view.