A private clinic, in which Dr Rhona Mahony and other obstetricians have an interest, asked the board of the National Maternity Hospital to defer its rental payments.
Dr Mahony, who is Master of Holles Street National Maternity Hospital, was present at the hospital's board meeting in September when the request was made.
She is among five doctors employed in Holles Street who are directors of the private maternity clinic, which is housed in a nearby building that is leased from the hospital.
It emerged at the Dail Committee on Public Accounts in November that the HSE is examining if the doctors have a conflict of interest because of their involvement in the clinic.
A spokeswoman for the HSE said this week: "The particular review is being progressed by the Regional Directors of Performance and Integration (RDPIs) for HSE Dublin mid-Leinster and further information will be available in due course."
A spokesman for Holles Street declined to comment on the application to the board to defer the payments or say what sum was involved.
The documents obtained under the Freedom of Information Act by the Irish Independent show the board asked for further information from the Merrion Fertility Clinic.
Dr Peter McParland, who is also a director of the private clinic, was also present for the board meeting.
The website of the Merrion Fertility Clinic states that it is is a multi-disciplinary team of professionals who are committed to providing the best possible fertility service.
It says: "We pride ourselves in our individualised approach to patient care, in the context of the highest levels of medical safety and professionalism.
"Our doctors also work as consultant obstetricians and gynaecologists at the National Maternity Hospital, enabling them to access services in the hospital when required.
"Our proximity to, and close association with the National Maternity Hospital, ensures that we benefit from a range of expert services at the hospital; including full laboratory services, operating theatres and the ability to admit patients, should any complications arise, and consultant anaesthetists who provide sedation.
"Once pregnant, our patients can continue their pregnancy care at the hospital, if they so choose," it adds.
The document also shows that a circular from the HSE, pointing out the need for Holles Street to comply with public pay policy in relation to top-ups, was brought before the board meeting in September.
Holles Street is one of over 27 hospitals and agencies to have made business cases to the HSE to continue paying top-ups to a number of senior staff. It has made three business cases.
A board meeting early in 2013 heard of concerns about its €44.2m budget for the year. It included a provision to raise €1.3m from patients with private health insurance occupying public beds even though the legislation to allow the hospital impose this charge was still not in place.
The board noted there were a significant number of uncertainties around potential national costs, which may or may not be covered by its funding allocation from the HSE.