SEOUL, South Korea - Health officials have confirmed the second outbreak in the past week of bird flu at poultry farms in South Korea.

Government tests confirm that the deadly H5-N1 virus has infected ducks at a farm in Jeongeup, about 250 kilometres southwest of Seoul, said Lim Kyung-hwan, a quarantine official at the North Jeolla Province government.

Quarantine officials slaughtered 6,500 ducks at the farm over the weekend and have banned movement of all poultry within 10 kilometres of the outbreak site.

The duck farm is 27 kilometres away from a chicken farm where the H5-N1 strain was confirmed last week.

Seven outbreaks of the deadly virus hit poultry farms across South Korea between November 2006 and March 2007, resulting in the slaughter of about 2.8 million birds.

South Korea declared itself free of bird flu in June last year after reporting no new outbreaks for three months.

At least 238 people worldwide have died from bird flu since 2003, according to the World Health Organization.

So far, most human cases have been linked to contact with infected poultry.