Salvors have begun to raise the wreck of the frigate that sunk after a collision with a Tsakos Energy Navigation tanker in November.
Two crane ships started on Tuesday to lift the Helge Ingstad from the seabed off the west coast, the country's armed forces said, according to Reuters.
The work is expected to take five to six days if the weather stays benign.
The army has said it is evaluating whether it is possible to repair the 5,290-gt vessel.
The crew of the sunken warship did not realise they were headed toward the moving 113,000-dwt aframax TS Sola (built 2013) until it was too late, a preliminary investigation of the collision found.
The Accident Investigation Board Norway said the crew of the state-of-the-art naval ship, having just completed a watch change while returning from Nato exercises in the early morning hours of 8 November, thought the tanker was stationary until the two ships were within 400 metres of each other.
The frigate's crew then attempted an avoidance manoeuvre, but it was too late.
