The Health Service Executive is investigating alleged irregularities in dispensing fees claimed by Ireland's largest pharmacy group LloydsPharmacy.
LloydsPharmacy has rejected the allegations.
LloydsPharmacy Ireland has 93 branches nationwide making them the largest pharmacy group in Ireland.
Under normal circumstances pharmacies can claim a €5 fee for every drug dispensed on prescription under the GMS medical card scheme.
However, this investigation focuses on phased dispensing fees charged by the pharmacy group on their medication management system called MyMed - essentially a modern day pill box that segregates drugs into weekly packs for those on large amounts of medication.
Under HSE rules there are a very limited number of circumstances under which a pharmacy can claim additional charges for phased dispensing of one prescription.
Documentation provided to RTÉ by a whistleblower shows that LloydsPharmacy staff are actively encouraged to promote this MyMed system to its customers - in their weekly newsletter staff are reminded of the substantial profit MyMeds generates for the company.
In fact their own graphic demonstrates how a monthly five item prescription dispensed under normal circumstances would generate €25 in fees for the pharmacy from the HSE.
It illustrates the same prescription earns Lloyds over €74 in phased fees when charged through the MyMed system.
The graphic also shows that this one prescription could generate an additional profit of nearly €600 annually that is a 66% increase in dispensing fees for the pharmacy group.
However, the LloydsPharmacy newsletter does not mention the limited circumstances in which phased dispensing and the charging of multiple fees is allowed.
Prescriptions provided to the RTÉ Investigations Unit also show that on repeated occasions LloydsPharmacy customers were provided with a month's allocation of their prescribed drugs on the one day but payment statements from the HSE show that phased charges were submitted as if these drugs had been dispensed each week over a four-week period using the MyMed system.
LloydsPharmacy stores nationwide are required to meet monthly MyMed targets for the conversion of customers
As seen in a staff newsletter - branches that achieve their target are praised for their performance - while others are named and shamed for their poor rating.
While not naming the company, the HSE confirmed that it is in the process of carrying out investigations in relation to certain claims submitted for payment and while the review is still ongoing the HSE said it will take any action it deems necessary depending on the outcome of the investigation.
In a statement, LloydsPharmacy Ireland has said it "...strongly refutes the allegations relating to our phased dispensing service... and we fully adhere to the HSE's own phased dispensing guidelines, agreements and processes."
It says that "... the HSE is now interpreting these differently runs contrary to the clear understanding of the pharmacy community." They added that "... our staff incentive structures are currently under review."