The number of human cases of H7N9 bird flu in China this month has passed 100, according to an AFP tally, as the worst-hit province ordered live poultry markets in major cities to be closed.

H7N9 cases and deaths dropped significantly after the end of June last year but have spiked recently with the onset of winter.

So far this month there have been 102 cases in mainland China, including 22 deaths, according to an AFP tally of reports by local authorities.

In the whole of last year, China had 144 confirmed cases including 46 deaths.

The H7N9 human outbreak began in China in February 2013 and reignited fears that a bird flu virus could mutate to become easily transmissible between people, threatening to trigger a pandemic.

But there has been no evidence so far of sustained human-to-human transmission, say both Chinese authorities and the World Health Organisation.

More than half of this month's deaths, 12 fatalities, have been in the eastern province of Zhejiang, where state media said Tuesday live poultry markets would be permanently closed in major cities.

Live poultry markets are common in China and elsewhere in Asia, and present an ideal environment for virus spread between birds held together in very high concentrations.

Such facilities will be closed in major cities and affected smaller towns in Zhejiang for three months by February 15, and permanently in major cities from July 1, the Zhejiang Daily said, citing authorities.

It said the "painful" measure was being taken as part of efforts to combat the disease.