China has reported several cases of acute pneumonia in Hubei Province's Wuhan City, 1,500 km northeast of the border, since December, according to the ministry’s General Department of Preventative Medicine.

As of Tuesday 27 cases have been confirmed, with seven people reportedly in critical condition, it added.

The Chinese Ministry of Health is investigating the source of the infection and seeks to contain the outbreak.

There is no clear evidence yet that it has been transmitted between humans, with preliminary tests indicating it is an outbreak of viral pneumonia, according to the Vietnamese department.

The Vietnamese Ministry of Health is collaborating with the World Health Organization to keep its citizens updated on the situation and devise preventive measures.

The outbreak is suspected to be linked to severe acute respiratory syndrome, or SARS, which emerged in China in 2002 and spread to other countries, including Vietnam, in 2003, Chinese media reported.

More than 8,000 people were infected and 775 died.