At 6pm police officials reported that the bag's contents were harmless.
"There's nothing dangerous in the bag, I've just been told. We're going to start traffic up again as soon as possible, but passengers should count on delays continuing until at least midnight," said Jan Lindqvist, Swedavia's press spokesman, to news agency TT.
Parts of Landvetter's international departure hall were cordoned off following the discovery of the bag next to the international departure hall's security control, located on the second floor of the airport.
According to the police, no known threats have been issued against Landvetter airport, or against any of the airlines that fly from it.
The owner of the bag has been identified.
"He's not suspected of any crime, but we will be interrogating him," said police spokesman Stefan Gustafsson to news agency TT after the discovery.
"The image of the bag's contents forced us to call in our technicians to investigate it further," Gustafsson explained.
No flights departed or arrived to the airport for hours.
"The domestic hall is packed to the brim. People are sitting on the luggage belts and everywhere, but most of us are standing," said Elin Kerola, passenger headed for Stockholm, to TT.
"All we've been told is that flights are going to start taking off again as soon as possible, but nothing on when that might be. The hard part is not knowing anything."