China's deadly outbreak of H7N9 bird flu has spread to a province in the country's south, the government said Friday, marking the second announcement in two days of a case in a new location.

The local health bureau in the southeastern province of Fujian said a 65-year-old man was confirmed to have the virus.

On Thursday, the eastern province of Jiangxi confirmed its first case of H7N9, in a 69-year-old-man.

More than 110 people in have been confirmed with H7N9, with 23 deaths, since the government announced on March 31 that the virus had been found in humans. Most cases have been confined to eastern China.

The island of Taiwan has also reported one case.

A Chinese expert earlier this week warned of the possibility of more cases in a wider geographical area.

"Until the source of H7N9 is... brought under effective control, sporadic cases might continue to appear," said Liang Wannian of China's National Health and Family Planning Commission.

"The area of the epidemic might continue to expand," he was quoted by the official as saying on Wednesday.

Chinese researchers, reporting in The Lancet on Thursday, said they had confirmed poultry as a source of H7N9 flu among humans.

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

A visiting team from the (WHO), which wrapped up a week-long visit to China on Wednesday, said there had been no human-to-, but warned H7N9 was "one of the most lethal" influenza viruses seen so far.

Chinese health officials have acknowledged so-called "family clusters", where members of a single family have become infected, but have declined to call it human-to-human transmission.