The 1,600 clinics in the Community Health Assist Scheme (Chas), under which patients get subsidised treatment at private medical and dental clinics, will have to provide itemised bills from next year.
Dental claims will also be tweaked to be more specific about the work done.
In a statement yesterday, the Ministry of Health (MOH) said bills should list what the doctor or dentist charges, the amount of subsidy the patient gets and the amount they need to pay.
It should also list the consultation fee, cost of medicine, investigations and anything else that is charged. Dental procedures must also be itemised, such as the number of fillings carried out.
Bills will have to be issued from Jan 1 next year, even if a patient does not need to make any "out-of- pocket" payment.
It said this would "enable patients to better understand their clinic's charges and the Chas subsidies they receive".
About 1.3 million people, including those in the pioneer generation, are eligible for Chas subsidies. Last year, MOH paid out $167 million in subsidies for treatment given to 650,000 Singaporeans.
However, the scheme has not been without its problems. A few months ago, MOH suspended two dental clinics from the scheme. They are now the subject of a police fraud investigation.
Since then, several people have raised issues with the way some clinics manage this programme.
One writer to The Straits Times Forum page said a Chas clinic refused to issue a bill, asking why he wanted a bill when his treatment was free as it was entirely covered by the subsidy.
The ministry announcement did not allude to any of this, but it did say that the changes are to "enhance fee transparency".
It has also tweaked some dental subsidies, such as allowing up to only two root canal treatments a year
Currently, dentists can claim between $174 and $266.50 for root canal treatment for a pioneer generation patient.
From next year, the subsidy for the same patient will be $174 for a front tooth, $220 for a pre-molar and $266.50 for a molar. The subsidy will cover up to two root canal treatments a year.
MOH said: "We encourage Chas patients to speak to their clinics if they have any queries on their bill."
Correction note: This story has been updated for clarity.