"We know for certain that it is the H5 virus but we cannot yet say if it is H5N1, but we expect to get an answer in the course of a few days," Jan Mousing, director of the Danish Veterinary and Food Administration (DVFA), told a news conference.

The dead bird was found near the town of Naestved, about 70 km (44 miles) south of Copenhagen in the southern part of the island of Zealand in a wetland area with many migrating birds, officials said.

The Danish authorities set up a quarantine area with a radius of at least 10 km around the place where the bird was found, banned transport of birds out of the area and ordered that domestic fowl be kept indoors, another DVFA official said.

Denmark, a poultry producer with an output worth 3 billion crowns ($483.5 million) a year, has been on guard against bird flu since disease was found on the German Baltic island of Ruegen, near Denmark's southern coast in mid-February.

Denmark has since examined 230 dead birds for avian flu and will continue to examine many others, officials said. Sweden reported its first bird flu case on Feb. 28.

"We have been expecting this and are prepared," Jan Pedersen, General Manger of the Danish Poultrymeat Association, told Reuters. "We have further tightened our rules to make sure that the virus is kept out of our poultry sheds."

The H5N1 virus usually kills poultry within 48 hours and can infect people who come into close contract with sick birds.