The 44-year-old captain, a Ukrainian citizen, was more than four times over the legal alcohol limit when the ship ran aground near the Helsingborg port, Calle Persson of the Skåne police told AFP.
Persson said the captain had an alcohol level, as measured by a breath test, of 0.4 milligrams per litre, with the legal limit for navigating at 0.1 milligrams per litre.
He added the captain was arrested for “aggravated drunkenness at sea” even though aggravated drunkenness usually starts at 0.5 milligrams of alcohol per litre, because of the circumstances.
“It is a decision that was taken considering he was the commanding officer of a big ship that he was navigating in the shallow Öresund strait,” he said.
The 85-meter (278 feet) Flinterforest, a Dutch vessel, ran aground early on Friday a few kilometres north of the southwestern port of Helsingborg, on her way from Finland to Scotland with a cargo of paper rolls.
The Swedish coast guard, which was alerted at 5:30 am, said none of the five other crew members were hurt and that no fuel had been spilled.
Built in 2004, the Flinterforest cargo vessel belongs to a Dutch shipping company by the same name and is managed by two other companies: Flinter Management and Forestwave Navigation.
The ship’s commercial manager, Flinter, declined to comment.
“We cannot say anything about this as long as the investigation is ongoing,” spokeswoman Elise Croonen told AFP.
“The company is fully cooperating” with Swedish authorities probing the cause of the incident, she added.
In a statement, Flinter said there was no damage to the cargo ship and no danger of pollution.
“In cooperation with the local authorities and marine experts, Flinter is doing everything possible to refloat the ship in the safest possible way.”
Tomas Nilsson of the coast guard said authorities were still trying to determine how to free the ship, which is beached on gravel.
“We don’t think we’ll be able to free it before the weekend. To get it out, we’ll have to relieve it from its cargo, and another ship will have to come free it,” Nilsson told AFP.
Police spokesman Persson said a prosecutor had three days to decide if the captain was to be remanded in custody or not.