Patients are increasingly turning to C-class wards, which offer the highest subsidy levels of 65 to 80 per cent of the hospitalisation bill.
In 2000, 26 per cent of all public hospital patients opted for C class. Last year, 46 per cent did so.
Combined with B2 class, the proportion of public hospital patients choosing subsidised care went up from 70 per cent of the total number in 2000, or 194,000 patients, to 80 per cent last year, or 272,000 patients.
Mr Lo Chun Meng, 84, who was admitted to Changi General Hospital when he fainted while shopping in Bedok, said he opted for C class because it was the cheapest. He added: "The place is very nice."
The high demand for subsidised care comes despite most people having insurance for treatment in private wards or hospitals.
Health economist Phua Kai Hong of the Lee Kuan Yew School of Public Policy said: "Many Singaporeans are risk-averse - kiasu - and buy more insurance than necessary, for peace of mind.
"However, upon actual admission, they prefer lower-class wards based on the estimated bill size after financial counselling."
The Ministry of Health said the number of patients opting for the private A and B1 classes had fallen over the years and had recently "stabilised at around 68,000".
Although more subsidised beds have been added in recent years, with about four in five public hospital beds in B2 and C class, more subsidised patients have had to be assigned beds in a higher ward class.
Patients can choose any class ward, but the amount of subsidy they enjoy depends on their salary or value of their home; this ranges from 50 to 65 per cent for B2 and 65 to 80 per cent for C class.
If the ward class a patient picks is full, but beds are available in a higher-class ward, public hospitals are obliged to place him in the pricier ward while charging him at the rate of the ward class he chose.
In 2000, 5.4 per cent of subsidised patients needed to be placed in pricier wards. Last year, about 10 per cent found themselves in a higher-class ward than they paid for.
This is in spite of an increase in subsidised beds from 3,700 (69 per cent) in 2000 to 4,800 (79 per cent) last year. In contrast, over the same period, private beds in public hospitals shrank from 1,700 to 1,300.
With the Government paying at least half of the bill, the difference to the patient is huge.
For example, the median bill for a patient admitted to the Singapore General Hospital with uncomplicated pneumonia is $2,661 in A class and $612 in C class. If it is for a major procedure such as a heart bypass, the median bill for an A-class patient at the National Heart Centre is $32,037, compared with just $4,277 in C class.
Ms Tin Pei Ling, a member of the Government Parliamentary Committee for Health, said that with the launch of MediShield Life later this year, the demand for subsidised wards could go up even more.
She said if people find MediShield Life with its enhanced benefits sufficient for their needs, they may decide to drop their private plans.
If that happens, "subsidised wards will be all the more attractive compared with private ones".