In a meeting with journalists on Monday evening, confessed that that he had told police only that he had been in the car, and claimed that he had not been the driver.
"Initially, when I woke up, I was a bit unclear and did not give the correct information," the 28-year-old told VG newspaper. "I said I was in the car, but I assume that in the condition I was in, I did not remember what happened," he said.
Police on Monday confirmed that Northug is under investigation after causing an accident and admitting to drunk driving. Police in Trondheim, the western city where the incident took place, said they were waiting for the alcohol level test results "in the next 14 days" before they make a decision on any charges against the "enfant terrible" of Norwegian cross-country skiing.
"The police confirms that Petter Northug is being investigated for a violation of traffic regulations," officer Monica Groette Estenstad said during a press conference. "This case will be treated like any other of the same kind."
In the early hours of Sunday, Northug's black Audi A7 was found crashed into a road barrier after crossing a roundabout and knocking down several traffic signs.
Potentially aggravating factors are that the driver -- who has proven to be the sportsman himself -- fled the scene, leaving behind him a slightly injured passenger, and that the evidence on site point at a speed above the 40 km/h (25 mph) limit.
After being arrested at home and interrogated by the police, the 28-year-old skier issued a statement in the evening offering his "deep apologies" and saying he was "ready to accept the punishment for (his) actions".
"It's the alcohol level that determines the sentence," Estenstad said.
The legal limit in Norway is 0.2 gram per liter of blood, and a result above one gram is usually punished with imprisonment without remission.
Norwegian media speculated about the skier's future career in light of the incident. Northug holds four Olympic medals -- two gold -- but has been out of shape since last year and did not make the podium at the Sochi Olympics in February.