After discovering the H7-type avian influenza in live poultry Macau culled 7,500 chicken, say sources.
The decision to slaughter the chickens comes after Hong Kong's cull of around 20,000 chicken in January, after the deadly H7N9 bird flu virus was found in poultry also imported from China.
Macau authorities discovered a positive H7 sample in a batch of poultry imported from the mainland Chinese city of Zhuhai on Wednesday.
"To ensure public health, authorities have decided to take decisive action and ordered the emergency measures of culling, sealing off and disinfection," a government statement released Thursday said.
They did not give details on which strain of H7 flu was found.
The cull of the 7,500 chicken started at midnight and lasted six hours, a government spokeswoman told AFP.
Images on the government website showed health officials wearing masks and white protective suits placing chicken in large plastic yellow bags at the Nam Yue Wholesales Market.
The market -- Macau's only wholesale market for poultry imports -- will be closed for 21 days starting Thursday for disinfection, the government said.
A health department spokesman said that since 1999, there has not been a human case of avian flu in the territory.
In the neighbouring southern Chinese city of Hong Kong, the virus has claimed the lives of three men since December last year, and has infected six in total.
An 18-month-old girl, in the latest case announced in the city, was confirmed to carry the virus earlier this month after having recently returned from mainland China.
Hong Kong officials said last month that they were extending for four months a ban on live poultry imports from mainland China to guard against the disease.
The outbreak, which first emerged on the mainland in February 2013, has reignited fears that a bird flu virus could mutate to become easily transmissible between people, threatening to trigger a pandemic.
A total of 72 people died from the H7N9 bird flu strain in China in the first two months of this year, government figures showed, far more than 46 deaths in the whole of 2013.