An image published by Norwegian broadcaster NRK showed that water had nearly reached the level of the frigate's helicopter platform.
The crew were evacuated amid fears the vessel would sink.
Helge Ingstad took on water and all 137 personnel were evacuated, according to the statement, which added that eight suffered minor injuries.
The warship is now in danger of sinking, while the tanker, named the Sola TS, is slightly damaged and did not spill oil.
According to reports from the rescue crews, seven people have been lightly injured in the collision, and there has been no oil spilled from the tanker, which suffered a lot less damage than the frigate, which was returning from a North Atlantic Treaty Organisation military drill.
Eirik Walle, with Norway's rescue center, told Norwegian news agency NTB that the collision caused an opening in the frigate's hull and "it is taking in more water than they can pump out".
According to the Norwegian Coastal Administration, a 10-cubic metre helicopter fuel tank on the frigate was ruptured.
Norway's largest oil and gas company Equinor, formerly known as Statoil, said it shut down non-emergency activities at the Sture terminal "as a precautionary measure".
Norway's Accident Investigation Board, which has opened an inquiry, had initially said a tugboat had also been involved in the collision but the Navy later denied that.
The 62,000-tonne tanker sustained only slight damage and is waiting to be towed to a nearby oil terminal.
"A small oil slick from the frigate has been detected, but nothing large", the official added.
Several offshore rigs that were pumping their production into the Sture terminal, a major tanker port for crude oil, temporarily suspended the flow, Norwegian newspaper Dagens Naeringsliv reported.
Panthers offense explodes against Buccaneers
Newton said that when they got the ball back only up a score after being up 28, there was no panic from his team. This guy is on a mission and it's been handsome to see and be around".
Celebrities Who Suffer With Chronic Diseases
Now if that isn’t the epitome of what a BFF is, I don’t know what is! Selena continues to be on chronic medication. There is also a huge list of celebrities past like famous painter vincent Van Gogh who suffered with this disease.