Poland, the European Union's largest poultry producer, has reported an outbreak of the highly contagious H5N1 avian influenza virus among poultry in the northern part of the country, Reuters reported, citing the World Organisation for Animal Health (WOAH) on Tuesday.

The spread of avian influenza has raised concerns among governments and the poultry industry after it ravaged flocks around the world over the past few years, disrupting supply, fuelling food prices and raising the risk of human transmission.

The outbreak was found in a backyard with 80 domestic birds, the Paris-based body said, citing information from Poland's health authorities.

Avian influenza usually strikes during the autumn and winter. It is transmitted via the faeces of infected migrating wild birds or by direct contact with contaminated feed, clothing and equipment.