Duchas, the Heritage Service, has expressed concerns about a proposal to build a 106-bedroom hotel opposite King John's Castle in Limerick city centre.
The developer, BQ Enterprises, is awaiting a planning decision after resubmitting its application last December.
This followed an application which was turned down last year because of the proposed hotel's scale and inappropriate character.
Dúchas has stated that the new application for a three-storey building at the Northern Relief Road has taken on a number of their concerns regarding the hotel's impact on the surrounding townscape - and says it "should not detract from the amenity of the adjacent historic buildings".
"A number of issues remain to be clarified, however, in order to ensure that the development would be of the highest standards befitting its location in the historic city, which relate principally to the external materials and finishes to be used."
The State body has recommended the use of environmentally sustainable building materials and added that PVC windows were not acceptable. It said samples of colours for the roofing, aluminium cladding and natural stone cladding should be submitted to Limerick City Council.
The city manager, Mr Brendan Keating, has also requested clarification of the materials proposed and said the roof design should be less intrusive than that in the plan.
A number of residents in the area have objected to the proposed 21-metre building's scale and design, claiming it would have a negative effect on King John's Castle and be out of context with the Bishop's Palace and St Munchin's Church.
Mr Tony Ryan of Katy Daly's pub said: "It will take from the character and the ambience of this quaint pub which was established in 1789."
A decision is also awaited on an application by Ard Scoil Rís, the Christian Brothers school on the North Circular Road, to demolish a monastery on the site.
The application has been referred to the national inventory of architectural heritage section of Dúchas.
The demolition plan has been opposed by the Irish Georgian Society, which said the building formed part of one of the city's early suburbs. "It was one of many villas constructed in the early 19th century. "These buildings were built in a variety of styles. The Old Monastery, originally Shelbourne House, a cut-stone building, was built in the Classical style: It still has a fine portico, cornicing and the recessed windows that are a feature of this period," the society said.
"Apart from being a fine example of the style, it is one of the few that has survived; that would make its demolition at this time highly regrettable."