Namibia has banned the import of chicken and eggs from neighbouring South Africa, which is battling the worst bird flu outbreak ever to hit the country, the government announced Wednesday.

The move, which has immediate effect, was triggered by an "alarming" increase in cases of "highly pathogenic avian influenza", the southwestern African country's agriculture ministry said.

"Importation and in-transit movement" of live chickens, poultry meat, eggs and chicks from South Africa would be suspended "until further notice" it said.

One of the continent's major poultry producers, South Africa reported the first bird flu cases in commercial farms in April, according to an industry group.

Due to its proximity, South Africa was Namibia's "preferred supplier" of chicken, but the country imports poultry also from Europe and South America, agriculture ministry spokesman Jona Musheko told AFP.

Earlier this month, the South African Poultry Association (SAPA) said the nation was contending with two different strains of the virus, the infamous H5N1 and a new strain identified as H7N6.

Producer Quantum Foods said last week that this year it had lost almost two million chickens -- worth a total of more than 100 million rand ($5.3 million) -- because of the disease.

Bird flu does not typically infect humans. But H5N1 is increasingly infecting mammals worldwide, raising fears it could pass on more easily to people.

The virus has typically been confined to seasonal outbreaks, but since 2021 cases have emerged year-round, and across the globe, leading to what experts say is the largest outbreak ever seen.

SAPA said the number of avian flu cases in South Africa this year was higher than in any year since the first outbreaks were reported in commercial farms in 2017.