Pakistani authorities have reported a new outbreak of bird flu at a poultry farm in the country's northwest.

Theauthorities said Sunday tests conducted at laboratories in Islamabadconfirmed the presence of the deadly H5N1 strain of avian flu at a farmin Swabi district of the North West Frontier Province.

They say the owner of the farm informed them that some 4,000 birds had died recently and that the remaining 2,000 were culled.

Local health authorities are monitoring nearby farms and the farm workers are being tested.

Pakistan reported its first case of the deadly strain of H5N1 bird flu in early 2006.

The virus resurfaced in February of last year among chickens at a house near the capital of Islamabad. 

Some information for this report was provided by AFP.