WARSAW (AFP) - A new outbreak of the potentially lethal H5N1 avian flu has been detected in northern Poland where cases have already been reported, the Polish Agriculture Ministry said Saturday.

"Veterinary authorities received the results Saturday morning from the national laboratory that confirm the presence of the H5N1 virus in the samples analysed," said a ministry statement.

The virus was detected on six farms in Sadlowo Parcele, a village within a health security zone set up after an H5N1 flu outbreak was detected in nearby Zuromin.

Some 200,000 chickens from four farms will be slaughtered, according to the statement.

At the start of December, avian flu was reported on two turkey farms and an egg producing poultry farm around Zuromin. Two large chicken farms in the northeast of the country were also reported to have H5N1.

Each time, exclusion zones were ordered. More than 500,000 birds were slaughtered.

The European Commission halted all fowl exports from the infected regions on December 3. Lithuania, Russia, Ukraine and Belarus have banned live fowl imports from Poland.

H5N1 has caused 209 deaths around the world since it was first detected in Asia in 2003.

The deadly H5N1 strain has passed from human to human only in very rare cases but scientists fear that such transmission could become more efficient and widespread through mutation, causing a global pandemic.