Inner City Helping Homeless said the "issue of anti-homeless spikes at Gandon House" represents "a not on my doorstep attitude".
Gandon House, Amiens Street, Dublin 1 is a building leased from a private landlord by the Office of Public Works.
Inner City Helping Homeless claim that the Department of Social Protection use this building, the department who are primarily responsible for those at their most vulnerable in society.
Speaking at the building, Inner City Helping Homeless Director Anthony Flynn said: "This is the most unsympathetic way of dealing with the homeless crisis, it's a not in my doorstep attitude and we certainly condemn it.
"The department has shown a real lack of consideration and empathy and I would like to hear their reasons.
"The cost of implementation these homeless measures I’m sure could have funded the opening of a boarded up unit around the city. This is not the way we should be dealing with the city’s homeless".