The girl, from the eastern province of Zhejiang, died on Monday night becoming China's 10th recorded death from the virus.
Her death comes days after the government confirmed that a 32-year-old man had died from the H5N1 strain of the bird flu virus in the southern province of Guangdong, near Hong Kong, triggering alarm there.
Yin Chengjie, the deputy agriculture minister, said: "The epidemic situation is very severe. Right now is spring, when there is a high chance of bird flu outbreaks due to the frequent movement of migratory birds. This epidemic has not been effectively controlled worldwide."
Albania on Wednesday confirmed its first case of H5N1 in a chicken found in the southern Sarande coastal region, close to the border with Greece.
To try to combat the growing threat, the United Nations' Food and Agriculture Organisation (FAO) is to play a greater role in fighting bird flu, becoming a "global clearing house" for efforts to stem the spread of the virus, it said on Tuesday.
The US and EU have backed the formation of an emergency operations centre at the FAO's Rome headquarters.
"There is a possibility there could be human cases of H5N1 in places without outbreaks of the disease in birds"
Funding will come from a pot of almost $2 billion pledged by wealthy nations at an international conference in Beijing in January.
The United States would provide experts to help run the centre and expects other nations to follow suit.
The deaths have raised questions in China over how the virus is spreading.
The 32-year-old man is the first bird flu death in an urban centre in China and occurred in an area where there have been no reports of the disease in birds.
He was believed to have contracted the virus at a poultry market.
The girl had visited relatives who kept poultry, and some chickens raised there had died during at least one of her visits, Chinese state media said.
Zhong Nanshan, director of the Guangzhou Institute of Respiratory Diseases, said both victims might have been infected by chickens carrying the virus but not sickened by it.
"There is a possibility there could be human cases of H5N1 in places without outbreaks of the disease in birds. That is, there could be chickens carrying the virus but which are not sick themselves and they can infect people," he said.
Scientists fear it is only a matter of time before the virus mutates into a form that passes easily among people, triggering a pandemic.
Millions could die and economies would be crippled for months.