The H7N9 bird flu virus has killed 20 people in China this year, with the total number of human infections now 102, according to the Chinese Center for Disease Control and Prevention.
That compares with 144 confirmed cases, including 46 deaths, in the whole of 2013.
But Shu Yuelong, director of the Chinese National Influenza Center, said a large-scale H7N9 epidemic is unlikely during the Spring Festival holiday, as no H7N9 virus mutation that could affect public health has been identified so far, Xinhua news agency reported.
"There is no evidence of constant inter-human transmission, and the risk assessment of H7N9 epidemic outbreak is unchanged," said Shu.
Shu reiterated that H7N9 is more prone to human infection than H5N1, with H7N9 case fatality rate reaching 20 to 30 percent.
Twelve people have been killed by H7N9 bird flu in Zhejiang Province this month.
More than half of China's cases this year have been in Zhejiang, with another 24 in Guangdong in the south.
Shanghai has reported eight cases of H7N9 bird flu this year, with two deaths — a 31-year-old emergency room doctor and a 77-year-old farmer.
It was not clear whether the rise in reported cases is due to the virus becoming more widespread and possibly less severe, or detection and treatment improving. Cases and deaths dropped significantly after the end of June, but have begun to pick up with the onset of winter.
China has dropped its previous description of H7N9 bird flu as "infectious" in new guidelines on how to deal with the disease.
The National Health and Family Planning Commission described it as a "communicable acute respiratory disease" in its 2014 diagnosis and treatment protocols.
In the 2013 version it was considered to be an "infectious disease."
"So far, most cases have been sporadic and there were some cluster outbreaks among family members," the commission said in the guidelines.
"But there is no evidence of sustained human-to-human transmission yet," the commission said, although it added that "limited" and "unsustained" infections could not be ruled out.
Dr Lu Hongzhou, director of Shanghai's expert group for H7N9 diagnosis and treatment, said a close contact with H7N9 bird flu patients displaying serious symptoms may get infected, but such inter-human transmission was rare.
Meanwhile, China's top quality watchdog has ordered strengthened efforts to control and prevent H7N9 bird flu with measures including temperature checks on people entering or leaving the country.
The General Administration of Quality Supervision, Inspection and Quarantine said anyone found with flu symptoms such as a fever, coughing or difficulty in breathing should be examined and taken to hospital immediately if found to be infected.
In Hong Kong approximately 20,000 chickens are to be killed after the H7N9 virus was discovered in a batch of poultry imported from China's mainland.
The positive reading came just days after the city introduced widespread testing of imported live poultry following public concern, AFP reported.
Two people have died from the virus in Hong Kong since the first infection was reported in December.