GENEVA: International experts are poised to head to China to probe the outbreak of H7N9 bird flu which has claimed 14 lives, the World Health Organisation said on Tuesday.

The mission, including four international flu specialists, is due to arrive in China in the coming days for a week-long investigation, the United Nations' health agency spokesman Glenn Thomas told reporters.

“At this time, there is still no evidence on ongoing human-to-human transmission,” Thomas underlined. “We're still trying to find out more information about the virus reservoir,” he added.

All told, the H7N9 strain of avian influenza has been confirmed as having infected 63 people since Chinese authorities announced two weeks ago that they had found it in humans for the first time.

Experts fear the prospect of such viruses mutating into a form easily transmissible between humans, which would have the potential to trigger a pandemic.

Health authorities in China say they do not know exactly how the virus is spreading, but it is believed to be crossing from birds to humans, prompting mass culls in several cities.

The United Nations' Food and Agriculture Organisation has said H7N9 shows “affinity” to humans while causing “very mild or no disease” in infected poultry, making it more difficult to find the source of transmission.

In 2003 Chinese authorities were accused of trying to cover up the outbreak of Severe Acute Respiratory Syndrome, which went on to kill about 800 people worldwide. But China has been praised for transparency over H7N9, with the WHO saying it was pleased with the level of information