Two more cases of people infected with the H7N9 strain of bird flu have been reported in Guangdong, according to a statement from the provincial centre of disease control and prevention.
One patient is a 29-year-old man who sells bean curd at a market in the Tianhe district of the city.
He became sick on January 3 and was admitted to hospital on Thursday. He is in critical condition.
The other patient is a 76-year-old man in Shenzhen. He also fell ill on January 3 and is in a stable condition in hospital.
So far, Guangdong has confirmed 14 human cases of the H7N9 virus since August. Hong Kong's secretary for food and health, Dr Ko Wing-man, yesterday called on people in Hong Kong not to visit markets in Guangdong or eastern mainland when they visited their relatives during the Lunar New Year holiday.
But the food and health chief said there was no need to ban all live chicken imports from the mainland. He said chickens imported into Hong Kong were raised separately from poultry sold on the mainland.
"There are no direct grounds to say that chicken breeding places that send chickens to Hong Kong are questionable because there are problems with the markets in the mainland," Ko said. No traces of the virus have been found on mainland farms, he said.