Twenty families are at risk of losing their homes after being told the apartments they're living in near Clondalkin never got planning permission.
45 apartments were built at Larkfield House on Coldcut Road, but the developer was only ever given approval to build 27.
South Dublin County Council has now stopped helping tenants pay their rent, and the owner of the building has given them a month to pay up or move out.
Campaign spokesperson and East Wall community activist Joe Mooney said "The purpose of our Campaign is to ensure that those who are causing the housing crisis - government, banks, estate agents, developers and rouge landlords - are not allowed to continue with 'business as usual."
"While thousands of children live in emergency accommodation we will NOT allow the situation to be normalised", he said.
Housing activist and spokesperson for the campaign David Gardiner said "Our campaign believes that the creation of a new system of universally accessible public housing is the only way to solve the housing crisis."
"That means providing public housing for anyone who wants it - including the many middle income earners who cannot get a mortgage. Proper provision of public housing is the solution to the problem of rouge landlords and their agents."