SINGAPORE - It is "just a matter of time" before the first case of Middle East respiratory syndrome (Mers) is detected in Singapore, Prime Minister Lee Hsien Loong said on Thursday.

Mr Lee and his wife Ho Ching were visiting Tan Tock Seng Hospital (TTSH) - Singapore's designated isolation centre for suspected and confirmed Mers patients - to observe emergency preparedness measures there.

Speaking to reporters inside the hospital's Communicable Disease Centre, Mr Lee stressed that Singaporeans must be especially vigilant now that the virus, which originated in the Middle East, has spread to South Korea.

"Every month we have about 40,000 visitors and during a holiday month like June, a lot of families go to Korea on holiday," he said.

Typically, patients who arrive at TTSH's emergency department with symptoms of respiratory illness, having visited South Korea or the Middle East, would be isolated for up to 48 hours if suspected of having Mers.

Doctors will take a sputum sample or a swab from their nose or throat to test for the virus.

Confirmed cases will be housed in either of the hospital's Communicable Disease Centres, which are separate from the main hospital building. All staff attending both suspected and confirmed Mers patients will be dressed in protective gear.

Suspected cases from other hospitals will also be taken to TTSH by ambulance.

In South Korea, more than 120 people have been infected by the virus and nine have died.

linettel@sph.com.sg