A mysterious disease that has killed at least 52 children in Cambodia since April was not been detected in China, a Ministry of Health spokesman said.

Deng Haihua told a press conference on Monday that the ministry was "highly concerned" about the situation in Cambodia after the World Health Organization reported the undiagnosed illness to member countries.

"China has reported no such cases to date," Deng said.

International health experts working to identify the illness have found a link to a virus that causes hand, foot and mouth disease, the WHO said in a statement.

Recent laboratory results showed a significant proportion of the samples tested positive for Enterovirus 71 (EV-71), which causes a lethal strain of hand, foot and mouth disease.

EV-71 is common in Asia, but was first detected in Cambodia.

The Cambodian health ministry has reported 59 cases of the undiagnosed illness in children aged 3 months to 11-years-old since mid-April. Of the 59 children, 52 died from the illness.

Symptoms of the unknown disease include high fever and rapid deterioration of respiratory function.

The WHO said identification of the viral strain was an important first step, but stressed more tests were needed to learn if the deceased children also suffered from other viruses.