The Swedish board of Agriculture said that it was raising its threat level to two on a scale of three as a precaution, meaning all poultry should be kept indoors.
"We are raising the level of protection as a precaution. Bird flu is spread mainly by wild birds and therefore the risk of getting the disease to the Swedish poultry is now considered elevated," Karin Åhl of the Agriculture board said in a statement.
The H5N8 bird flu has been found at a poultry farm in northern Denmark, the country's environment and food ministry said on Monday.
"The bird flu detected can have major consequences for Danish exports of poultry," the ministry said.