The Health Ministry expects this to cut the out-of-pocket payments for about 300,000 private patients a year.

Announcing the change earlier this year, Health Minister Khaw Boon Wan said it was in response to calls by middle-income people who wanted to use their hefty Medisave accounts rather than dip into their pockets to pay for hospital treatments.

Patients in B2 or C class wards with healthy Medisave accounts rarely need to pay any cash for their hospital stays. This is because of the heavy subsidy they get, which ranges from 50 per cent to 80 per cent of their bill.

The amount of Medisave withdrawal allowed depends on the type of operation and used to range from $150 to $5,000. From Monday, this goes up to $250 to $7,550.

So a patient in A class who goes for a knee transplant can expect to stay in the hospital for six days with a bill of about $13,500.

Under the old limits, Medisave would have picked up $5,900, leaving the patient $7,600 to settle with cash. Now, Medisave picks up almost $2,000 more.

However, patients who are well covered with insurance are unlikely to benefit from the change.

Read the full report in Monday's edition of The Straits Times.