The Office of Public Works (OPW) was told that three historic structures in the Botanic Gardens were in danger of collapse and that loose glass panels in the buildings were a safety hazard to the public and staff.
The Aquatic House - a complex of three buildings in the Gardens - had "significantly deteriorated" because of weather, timber decay and rusting ironwork.
An internal report said the dismal condition of the complex was in "direct contravention" of the OPW's legal responsibilities to safeguard the buildings.
Last month, the OPW announced a €250,000 emergency project to stabilise the Aquatic House and remove all vegetation from the three structures.
They said they hoped eventually to "faithfully restore" the buildings and reopen them to the public, subject to the availability of funding.
The Aquatic House complex dates from 1854 and was, according to an internal OPW report, considered of "significant architectural and historical importance".
Despite that, the three buildings - the Cactus House, the Victoria Water Lily House, and the Fern House - were allowed to fall into such disrepair that they had to be closed to the public in 2007.
They had been surrounded by hoarding and protective netting because of incidents of "blown out glass". This had been a risk to members of the public and the buildings continued to deteriorate.
A recent survey of the complex warned: "The resulting effect of this accelerated deterioration is that the complex is now in danger of significant further loss of fabric and/or potential collapse should immediate emergency works not be progressed."
The survey added that the current "distressed and delicate" condition of the building raised serious concerns, including the health and safety of staff and visitors. It also said that there was a legal responsibility on the OPW to take care of protected structures.
"The current poor condition of the complex is in direct contravention of the requirement for an owner to ensure that a Protected Structure is not endangered," it added.
The survey said plant growth needed to be cut back, emergency stabilisation put in place, and protection from weathering put in place. The report says the first part of the complex was built in 1854 to house what was described as the "botanical sensation of the time" - the Amazonian water lily.
The Cactus House was added in 1890, while a Fern House - home to an Australian tree fern reputed to be 400 years old - was built in 1969.
The detailed survey of the complex found "extensive corrosion" to wrought iron beams that supported the roof structure of the Cactus House. Glass panels from the roof were also missing, while others were loose.
"Any glazed panes that are detached from the roof could cause a significant health and safety risk to members of the public in the vicinity of the house," the survey added.
An OPW spokesman said Phase 1 works have commenced on the complex, which was the "first step" towards a fuller restoration in the years ahead.
He said: "Total project cost for Phase 1 will be €250,000, including VAT and professional fees. In Phase 2, which will be subject to the availability of funding, the OPW plans to faithfully restore the Cactus House and the Water Lily House and provide a new, redeveloped Fern House."