South Korea on Wednesday reported eight new cases of Middle East Respiratory Syndrome (Mers), while another person infected with the virus died, health officials said, bringing to 20 the number of fatalities in the outbreak that began last month.

A total of 162 people in South Korea have been infected in the outbreak, the largest outside Saudi Arabia. It has been traced to a 68-year-old South Korean man who returned from a business trip to the Middle East in early May.

South Korea's health ministry said 19 people diagnosed with the Mers virus had recovered and been discharged from hospital since the outbreak began.

The latest Mers patient to die in South Korea was a 54-year-old woman who had bronchiectasis and high blood pressure. All of the people to die in the outbreak had existing ailments or were elderly.

All of the infections known to have occurred in South Korea have taken place in healthcare facilities. Three hospitals have been at least partially shut and two have been locked down with patients and medical staff inside.

More than 6,500 people are in quarantine, either at home or in health facilities.

The World Health Organization (WHO) has called the South Korean outbreak "large and complex".

The eight new cases reported on Wednesday marked an uptick from the four and five on the previous two days, but below double-digit daily increases reported last week.

Mers is caused by a coronavirus from the same family as the one that triggered China's deadly 2003 outbreak of Severe Acute Respiratory Syndrome (SARS).

The vast majority of Mers infections and deaths have been in Saudi Arabia, where more than 1,000 people have been infected since 2012, and about 454 have died. – Reuters