"According to the official British tests, the three dead swans found in Hungary last week had the H5N1 bird flu strain," spokesman Andras Batiz said in a statement.
The samples were sent to the specialist laboratory in the UK after initial tests in Budapest last week, according to the statement.
The spread comes after tests confirmed another 22 cases of bird flu on the German island of Ruegen, bringing the number of cases to 103, mostly on the island.
A poultry cull has been ordered for the area, with troops deployed to help clear away dead birds.
Bird flu was first confirmed on the island last week, and infected wild birds have also now been found on the mainland.
Indian inquiry
Meanwhile, Indian officials have admitted failings in their bird flu surveillance system after the country's first case of H5N1 was only confirmed 25 days after chickens started dying.
A senior expert promised to conduct an internal inquiry to look into why it took more than two weeks for officials to be notified of the bird deaths, which began January 24 near the town of Navapur in the western state of Maharashtra.
Chicken sales in the country have plummeted since the news broke.
Malaysia has announced a fresh outbreak, the first in over a year, and said it will slaughter all poultry in and around four villages in central Selangor state.
Late on Monday Malaysia confirmed a new outbreak after 40 chickens died in four villages just north of the capital, Kuala Lumpur.