St Vincent's University Hospital in Dublin has told Minister for Health Leo Varadkar that the current plan to move the National Maternity Hospital in Holles St to the St Vincent's campus "carries a risk of compromising our patient care".
The hospital says it has sought answers to questions about the plan for several months.
The National Maternity Hospital is due to move to the St Vincent's Hospital campus in 2018.
However, St Vincent's says that key issues have been raised since November 2014.
In a letter, seen by RTÉ News, the hospital says it believes it can shorten the time required for the project, if key issues are dealt with.
The hospital says it wants more control over the project, given the potential impact on its existing campus activity.
The hospital says key concerns include the fact that existing patient care is in no way affected by the project.
It is also concerned that shared services are handled in the best interests of campus efficiency and that its future development plans are not compromised.
Separately, the hospital has agreed to an independent audit with the Health Service Executive on four key issues.
Firstly, if the hospital is meeting all public sector pay guidelines.
Secondly, if certain consultants are entitled to private work at the nearby private hospital.
Thirdly, if there is any cross substation of the public facility of the private hospital.
Fourthly, issues relating to the banking security arrangements on the public facility.
