A total of 6,941 flu cases were confirmed among inbound passengers in December and January, according to the General Administration of Quality Supervision, Inspection and Quarantine.
It marked a yearly increase of 81.9 percent, the administration said.
Chinese inspection and quarantine authorities require inbound tourists to notify symptoms such as fever and cough.
Unlike cases of serious infectious diseases such as cholera, inbound passengers with flu do not require mandatory quarantine at places designated by authorities, Liu Maohua, an official with the administration was quoted as saying by China Daily.
The inspection and quarantine officers may give a note to inbound passengers suspected of having the flu, suggesting they get an official diagnosis, Liu said.
The upcoming Spring Festival holiday and winter vacations have brought an increasing number of Chinese travelling abroad.
The administration also warned that travellers should take flu precautions before heading to countries and regions with high flu infections.
Flu outbreaks have been reported worldwide including the United States, Canada, Britain, Italy, North Africa, Japan and South Korea since winter last year. In the United States, 14,000 people were hospitalized for treatment as a result of flu.
Chinese authorities will follow and evaluate flu outbreaks in these countries and regions and intensify disease prevention and control at the ports.