Only 14 patients from China's H7N9 bird flu outbreak are still in hospital, national health authorities said in their latest update on the disease.

A total of 131 confirmed human infections of the virus have been recorded on the Chinese mainland, the National Health and Family Planning Commission said.

Of those, 39 died and 78 had been released from hospital, with 14 still being treated, it said in a statement late Sunday, adding it would no longer report figures weekly, switching instead to monthly updates.

One other case was recorded in Taiwan.

Experts fear the possibility of the virus mutating into a form easily transmissible between humans, with the potential to trigger a pandemic.

Laboratory tests showed that in some patients the H7N9 virus was resistant to treatment drugs, researchers in China wrote in the medical journal The Lancet last month, adding that their findings were "concerning".

But flu viruses are often seasonal and much of China has experienced warmer weather following the end of winter.