BEIJING (AFP) - A 44-year-old woman in southern China who tested positive for bird flu died on Monday, health officials said, in what is likely the country's third reported death from the virus this year.

The migrant worker, surnamed Zhang, died after developing a fever and a cough following contact with dead poultry in Guangdong, the province's health department said, although authorities in Beijing did not immediately comment.

In the financial hub of Hong Kong, which borders Guangdong, officials reacted by increasing tests of poultry coming over the border, although there was no ban on imports as occurred in similar cases previously.

The Guangdong health department said Zhang died in hospital after developing a fever, cough and inflammation of the lungs on February 16.

"We undertook tests on the patient and found that ... a test for the bird flu virus (H5N1) was positive," the department said in a statement.

"It was determined that before her illness she had had contact with dead poultry," the statement added, without saying specifically that the suspect fowl had H5N1.

The department said that no-one else who had come into close contact with the victim had shown any symptoms of the virus.

The central health ministry did not confirm the case. "We have no information," an official at the ministry's media office in Beijing said when contacted by AFP. In China, the central government authorities carry out their own tests for bird flu cases.

The World Health Organisation's China representative, Hans Troedsson, said the Chinese health ministry had informed his office of the potential bird flu case on Sunday.

If confirmed as a bird flu-related death, it would be the third in China since the start of 2008.

A 41-year-old man died of the virus in the southern Guangxi autonomous region on February 20, while a 22-year-old man in central Hunan province died on January 24.

Not including the death of Zhang in Guangdong, 19 people have been confirmed to have died of bird flu in China since 2003, while 10 others have recovered after catching the virus.

The latest deaths come despite China conducting a huge campaign last year to contain the disease, during which it attempted to vaccinate its entire tens of millions of poultry and stepping up public education efforts.

Hong Kong authorities appeared to be monitoring the Guangdong case very closely and gave more details than Chinese officials.

Zhang farmed poultry at her home and ate chicken after it had fallen ill and died, Thomas Tsang, the controller of the Centre for Health Protection of the Department of Health in Hong Kong, said.

The Hong Kong government has strengthened its border control, will continue to do temperature checks on those entering the territory and step-up inspections of imported poultry, Tsang told reporters.

Anyone who entered the city from the Guangdong province in the past six months and catches pneumonia must be tested for bird flu, he added, but there were as yet no plans to ban poultry imports from the province.

Bird flu has killed more than 200 people worldwide, according to the World Health Organisation.

Scientists fear the virus could eventually mutate into a form that is much more easily transmissible between humans, triggering a global pandemic.