Hong Kong culled around 20,000 chickens on Tuesday after finding the deadly H7N9 bird flu virus in poultry imported from mainland China, days before the Lunar New Year.

Fears over avian flu have grown following the deaths of two men from the H7N9 strain in Hong Kong since December. Both had recently returned from mainland China.

The number of human cases in China this month is 102 with 22 deaths, according to an AFP tally, and the worst-hit province of Zhejiang has closed live poultry markets in major cities there.

Officials wearing masks and protective suits piled dead chickens into black plastic bags at Hong Kong's Cheung Sha Wan market where the virus was found, television footage showed.

Cheung Sha Wan -- Hong Kong's only wholesale poultry market --- is now shut for 21 days for disinfection.

Vendors are unable to buy live chickens and farmers have nowhere to send their stock, leaving traders and shoppers disappointed during the holiday period.

Traditionally, locals buy a live chicken for Lunar New Year celebrations with family.

"I wanted to buy one for my mother for the festival," one shopper in the city's Wan Chai Road food market told AFP.

"But now there is none, I will have to buy something else. Live chickens just taste better than frozen chickens. The texture is different," said the woman, who gave her name only as Monica.

At a nearby live chicken stall the cages were empty.

"Of course there is inconvenience because we still need to pay the rent and we want to get paid. The sales volume will be affected," said a 59-year-old trader who gave his surname as Law.

Protest at slaughter

The mass cull started at 10:00 am local time and was completed by around 11:00 pm, said a government statement late Tuesday.

"A total of 22,604 poultry, including 16,984 chickens, 2,898 silky fowls, 1,080 pheasants and 1,642 pigeons were destroyed. They were sent to landfills for disposal," it said.

Chickens would be given a "chemical treatment" to kill them, an agriculture department spokesman said earlier.

Hong Kong last week introduced widespread testing of imported live poultry following growing concern over the safety of imports, particularly from the mainland.

Local chicken farmers and wholesalers questioned why chicken imports suspected to contain viruses had not been stopped at border checkpoints, but a government spokesman told AFP that there was nowhere to keep them.

"The government should be held fully responsible. It should have stopped the chickens at the border until they were confirmed to be clear of bird flu," wholesaler Cheng Chin-keung told the South China Morning Post.

"Now the chickens from China get mixed with local chickens in the wholesale market and all of them have to be culled."

He said he would lose HK$5 million ($650,000).

The city's health minister, Ko Wing-man, said the government would consider a "mechanism" to separate local and imported chickens.

A dozen chicken traders protested outside the residence of Hong Kong leader Leung Chun-ying Monday night.

But Leung called into question the tradition of buying live chickens for fresher meat.

"In the long run, should we keep the customs of eating live chickens? Hong Kong people should look into this issue," he told reporters.

Lessons from SARS

Strains of the H5, H7 and H9 avian influenza subtypes have long been present within bird populations and can cause human infections, primarily following direct contact with infected poultry.

The most common strain H5N1 has caused a confirmed 649 infections in humans and killed 385 people across 15 countries since 2003.

The H7 subtype was only present in bird populations until the appearance of the H7N9 outbreak in China in February 2013 where it is believed to have primarily spread through live poultry markets.

The emergence of a new subtype has reignited fears that the virus could mutate once more to become easily transmissible between humans, potentially triggering a pandemic.

Hong Kong is particularly alert to the spread of viruses after an outbreak of Severe Acute Respiratory Syndrome (SARS) swept through the city in 2003, killing 299 people and infecting around 1,800.

In December 2011, the city culled 17,000 chickens and suspended live poultry imports for 21 days after three birds tested positive for the deadly H5N1 strain of bird flu.

China has previously been accused of trying to cover up disease including SARS.

But the World Health Organization (WHO) has more recently praised its openness and response to the outbreaks of bird flu.

"We've been getting lots of timely, very full information from the Chinese. We're collaborating and speaking to them daily about the situation," WHO spokesman Glenn Thomas said Tuesday.

"If you compare the situation now to the last seasonal series of outbreaks, they're very similar. So there's no sense of this being out of control, or that it's getting worse or getting better. It's very comparable."