They are not the same as day surgery procedures, whereby patients spend just a few hours in hospital for simple operations, like the removal of breast lumps or piles, and do not spend the night there.

The previous practice was to admit patients the day before an operation, to run tests and complete paperwork.

Now, this is done a few days ahead of the scheduled procedure.

Patients benefit from a reduction in bills and stress, but it was mostly a crunch for beds which led hospitals to find new ways to free up more space.

Over the last few years, all public hospitals have begun same-day admissions and the numbers have built up gradually. Hospitals found that it did not affect patients adversely and that many patients preferred it.

Mr Soh Thiam Teng, 51, who needed a prostate operation at Singapore General Hospital (SGH), called it 'a very good initiative'. The building facilities manager, whose company picked up his hospital bill, said: 'It saved me the anxiety of spending an extra day in hospital.'

SGH had 7,300 same-day admission patients last year, or almost half its elective surgeries. SGH chief operating officer Foo Hee Jug said it had saved patients $700,000 and freed up 20 beds a day at the hospital, an important consideration with the growing demand for hospital beds.

The National University Hospital had 3,700 such patients (60 per cent of elective surgeries), Tan Tock Seng Hospital had 3,400 (68 per cent), Alexandra Hospital had 1,400 (68 per cent) and Changi General Hospital had 1,300 (25 per cent).

A Raffles Hospital spokesman said the hospital had always admitted patients on the day of the operation for the majority of elective surgeries.

The change mirrors a trend in Europe and the United States of making hospital procedures more cost-efficient in the face of rising health-care costs. Mr Foo said that at Boston's Brigham and Women's Hospital, 70 per cent of non-emergency surgical patients are admitted on the day of the operation.

In Singapore, the change from warding patients the day before surgery required changes to how hospitals functioned.

Under the old system, patients underwent various tests, such as X-rays and blood counts, once they were warded. Now, these are done a few days before surgery, along with the paperwork to make payment and give consent.

Nurses phone patients the day before surgery to remind them of last minute preparations.

Associate Professor Christopher Cheng, head of urology at SGH and an ardent supporter of the scheme, said that, while same-day admissions are now the norm in his department, he is careful not to compromise the welfare of patients.

Those who have multiple problems, diabetes, or other complicating illnesses which need watching over, are still admitted at least a day before, if not more, so that they can be carefully monitored before surgery.

But about 70 per cent of urology patients, such as Madam Siah Siew Kee, 43, who had cancer in one of her kidneys, now arrive on the day of surgery, at an arranged time, usually between 7am and 11am.

Within two hours of her arrival at 8.30am, her surgeon had done a quick check to make sure that everything was fine, and she was prepared and wheeled into the operating theatre.

The savings she enjoyed from spending a day less in a ward was less important than being with her family and sleeping in her own bed the night before surgery.

Said Mr Foo: 'Some patients get agitated while waiting in the ward. Many ask to be the first case 'to get it over with'.

'They can't sleep and worry the whole night without a sedative to calm them.'