The Construction Industry Federation has criticised regional planning guidelines, saying that they underestimate future demand for housing by up to 247,000.
According to the CIF statement, the most ambitious regional plans have a shortfall of some 140,000 housing units, leading to a view that the planning system is unprepared for the country's long-term housing needs.
The organisation carried out a review of the eight regional plans, which forecast a population of between 4.4 million and 4.7 million in 2020. The CIF says that this "significantly" underestimates population increases in Ireland.
"The CSO predicts that Ireland's population will reach 5.1 million by 2020," it said in a statement.
"Even this is a conservative figure when compared with what is currently happening, particularly in the area of inward migration. Based on the average household size of 2.84 persons, which is falling, the underestimation of population means that demand for between 140,000 and 247,000 is not factored into the strategies of the regional planning guidelines."