A Czech farm has been ordered to cull 750,000 hens – 15 per cent of the country's total – as Europe struggles to contain its worst outbreak of bird flu ever, authorities said on Wednesday.

The poultry farm in the western village of Brod nad Tichou is one of the Czech Republic's largest, Gabriela Dlouha of the Czech-Moravian Union of Poultry Breeders told AFP.

In recent weeks, more than a dozen Czech farms have also been affected by a virus that has wreaked havoc on farms across the EU.

"The situation is very serious. Ten new outbreaks were announced in the Czech Republic in December alone [and] the pace keeps accelerating," the state veterinary administration SVS said in a statement.

The SVS has already registered four new outbreaks this year, and egg prices are likely to rise because of the culling at Brod nad Tichou, Dlouha said.

Czech farmers had already been ordered last month to keep poultry indoors to try to stem the spread of the highly pathogenic H5N1 bird flu strain, which is potentially transmissible to humans.

European health authorities warned last month that the continent had seen the "most devastating" outbreak of the disease last year, when millions of birds had to be killed.

Some 2,500 outbreaks were detected on farms in 37 European countries between October 2021 and September 2022, with about 50 million birds slaughtered as a result.

Some 2,500 outbreaks were detected on farms in 37 European countries between October 2021 and September 2022, with about 50 million birds slaughtered as a result

Health authorities are studying the possibility of using vaccinations to halt the spread of the virus.

The European Centre for Disease Prevention and Control said the risk of infection in humans was low, and "low to medium" for people working in contact with birds and poultry.