Proposed MetroLink works at St Stephen's Green in Dublin will have a 'more than significant' impact on the area.
That is according to the Minister of State with responsibility for the Office of Public Works, Patrick O'Donovan.
He was speaking after the OPW warned the transport project would have a 'severe, negative' impact on the heritage value of the urban public park.
A MetroLink station is planned partly under Stephen's Green, but a consultancy firm acting for the OPW has told An Bord Pleanála the risk of damage to the park from the station is 'unacceptable'.
Minister O'Donovan told Newstalk Breakfast its history should be protected.
"St Stephen's Green is a particularly sensitive and vulnerable place," he said.
"It's the scene of a significant 1916 element to the Easter Rising.
"It's also very significant in the sense that it is one of the last parts of the remaining continuation of Georgian Dublin that's fully intact.
"We have responsibility for it, and we take that responsibility very seriously."
'Trees to be totally removed'
Minister O'Donovan said hundreds of trees would be impacted.
"What we're simply saying is giving a statement of fact on the basis of an application that's been made for a railway order having regard to the environmental, archeological, physical and historical changes that would be profound on a national monument," he said.
"If this was Kilmainham Gaol or Brú na Bóinne or the Rock of Cashel... we would be taking the very same position.
"The impact on the green is more than significant - you're talking about up to 220-odd trees being impacted, with almost 70 being totally removed.
"These are trees that are hundreds of years old.
"The actual national monument itself - which saw the engagement in 1916 - we know that when you dig up a national monument of that character, you can never bring it back.
"Once it's dug up it's gone - that's the reality."
He said it is not up to them to call for changes to the plans.
"It's not for us to suggest where the station should or shouldn't be, that's not our expertise.
"What our expertise, and what our department's responsibility is, is the preservation of the national monuments.
"It's not only for this generation but for future generations," he added.
MetroLink consists of a new fully segregated railway, most of which will be underground, between the Swords and Charlemont areas of the capital.
The route will also serve Dublin Airport - the first rail link to the country's largest airport - as well as major educational campuses.
Construction work is due to begin in 2025, with a view to it beginning operations in the early 2030s.