According to authorities, there is a high possibility that it is the N1 strain because of previous outbreaks in the area.

Officials said the H5 virus was detected on a farm in the northern province of Pichit, one of seven "red zone" provinces where surveillance was stepped up this month, and test results were expected in a few days. Compared to its slow response to initial cases in 2003, Thailand now has one of the strongest inspection systems in the area.

If H5N1 is confirmed, it would be Thailand's first confirmed outbreak of the virus in nearly nine months.

Livestock officials culled all chickens in the affected area and restricted poultry movements within a 10 km radius for at least 30 days.

An 11-year-old girl went to a Pichit hospital on Monday with flu-like symptoms after chickens died on her family farm where she had helped her mother bury dead chickens without any protective gear. Test results are due Tuesday.

The H5N1 virus has killed 14 Thais since it first arrived in the country in late 2003. The last death occurred in December 2005. The global human death toll is now at least 132 since the virus re-emerged in east Asia in 2003.