Some 200 years after it was born, Singapore's oldest and largest hospital is poised to become much larger and better equipped.

After the makeover, to take place over 20 years, the amount of space devoted to patient care at the Singapore General Hospital (SGH) campus, which includes five speciality centres, will triple.

The hospital itself will shift to another site nearby at the junction of Outram Road and Eu Tong Sen Street within the larger Outram campus, according to the masterplan unveiled by Prime Minister Lee Hsien Loong yesterday.

The high-patient volume services will be just a short walk away from the Outram Park MRT station.

"We have to do a musical chairs exercise," said Mr Lee. "Keep a very busy hospital running while shifting roads and buildings around."

By the time the masterplan is completed, almost 50 years would have passed since SGH's last redevelopment in 1981, said Mr Lee.

The hospital, along with its five speciality centres and polyclinic, already cares for a third of all patients in the country.

The coming decade will see four new buildings taking shape: the 550-bed Outram Community Hospital, National Cancer Centre, an interim emergency department, and part of the new bigger SGH.

Mr Lee pointed out that the new SGH campus will target areas where most demand is expected.

Cancer is high on this list, so the tallest building on the campus will be the new 20-storey National Cancer Centre. Mr Lee said it will have a lot more space than the current centre as demand for cancer care is expected to grow, as better treatment means longer lives for patients who will need follow-up care.

One of the hospital's busiest departments, Accident and Emergency, cannot wait for the new SGH and will require a new interim building to cope with rising demand.

The department handled more than 135,000 patients last year and this number is likely to grow.

An elective care centre for non-emergency treatments - complete with operating theatres, specialist outpatient clinics and wards - will form the cornerstone of the new SGH complex.

These new facilities will be designed to be more patient-centric.

In the next phase, several current buildings will make way for the new SGH complex, which should be ready in about 20 years' time.

Mr Lee said that to better understand diseases that affect Singaporeans, medical care, research and education will go hand in hand. The campus will house a research park for firms that work with healthcare providers, and an education zone where Duke-NUS Medical School is sited.

The campus will meet 40 per cent of healthcare training needs, said Mr Lee. It will train doctors, nurses and other hospital staff together as part of "integrated training".

Professor Ivy Ng, group chief executive officer of SingHealth, said the masterplan caters to both current and anticipated needs.