China has announced it had killed nearly 400,000 chickens in the far northwest of the country to control a fresh outbreak of bird flu.

The outbreak was discovered on July 14 in Aksu city, Xinjiang region, when 3,045 chickens were found dead, the agriculture ministry said in a brief statement on its website on Friday.

Since then 356,976 chickens have been killed as part of emergency measures to contain the outbreak, according to the statement.

"The epidemic is effectively under control," it said. There was no mention of any concerns for people living in the area.

The outbreak is the 37th reported among poultry in China since October last year.

Nineteen people have been confirmed to have contracted the H5N1 virus in China, 12 of whom have died.