The developers of Ireland's tallest building have been asked to justify the height of the 140 metre, 34-storey tower they have proposed for Cork's Custom House Quay.

City planners have requested further information on a number of elements associated with Tower Development Properties' plans for the site, causing a delay in the development.

Developers have up to six months to respond to the requests, which focus on height and fire safety, as well as the building's heritage and nature impact.

The proposal for the Custom House Quay site included a 140-metre tall skyscraper hotel, as well as the redevelopment of the historic bonded warehouses. There were also plans for retail, cultural, food, beverage and office elements to the plan, as well as a micro-distillery.

City planners this week wrote to developers outlining a range of areas where further information is required. They told the developers to "re-evaluate the justification for a tall building at this location" and noted that it will have significant impact on views from parts of the city.

"Some of these views are protected views in the City Development Plan... The assessment... may require amendments to the proposed height, design and external finishes of the tower element of the proposal," planners said.

There are also a number of concerns raised by the chief fire officer, including "the design of the project having regard to fire escape stairs, occupancy of floors and compartmentalisation".

The fire officer's report notes that two of the fire escapes exit into covered courtyards, which "would not be recognised as a place of safety by the Fire Department", while the potential maximum capacity of the top two floors of the building "exceeds potential maximum escape capacity of the escape stairs from that area".

Several concerns about the heritage impact of the development are included, too.

Specifically, planners say that the removal of the revenue building "is not considered to be acceptable" and that "a significant element" should remain. In the architectural design statement, developers had argued that it was necessary "to lose the interior of the Revenue Building in order to make way for the new contemporary addition by compensating for the loss with significant benefits to the city and public".

Planners also raised a concern about the lack of "specific maritime focus in the new conception of the site" and said that the removal and relaying of 19th-century cobblestones is also "not acceptable".

Concerns are also raised about the impact on biodiversity. Specifically, "measures should be taken to create artificial habitats for the sand martins through, for example, providing bird boxes in key locations".

Another element cited by planners relates to the pontoon on the site. It is used frequently by community groups, like Meitheal Mara, and the river search and rescue teams.

Planners directed developers to clarify that the pontoon "will have a continuing use... as a berthing facility and recreational use".