The number of prescriptions issued for medicines containing codeine has increased by more than 22% since 2012.
The latest figures were released in a reply to a parliamentary question from Fine Gael's health spokesperson Colm Burke.
Over one million prescriptions for the pain-relieving codeine drug were issued through public medicine schemes last year.
This is an increase of more than 17% since 2018 alone.
Mr Burke said it is worrying that the numbers for the overall population could be much higher.
This is because these figures do not include prescriptions paid for privately or for codeine products that can be bought over the counter.
The Fine Gael health spokesperson said there are longstanding concerns around the misuse of common non-prescription medicines containing codeine.
The Health Products Regulatory Authority is currently reviewing the sale and supply of codeine medicines available without a prescription.
Its findings will then be considered by the Department of Health.
