An Bord Pleanala has granted permission for almost 500 apartments in Saggart, in spite of opposition from Fine Gael's Colm Brophy and local residents.
A subsidiary of Pat Doherty's Harcourt Developments group sought permission for 488 apartments at Fortunestown Lane.
The grant to Greenacre Residential is part of 1,149 homes granted by the appeals board under fast-track legislation in recent days.
It also granted planning permission for 661 homes at Rathmullan Road, Drogheda, to Trailford Ltd.
The contentious Saggart plan, comprising five apartment blocks from five to nine storeys, faced local opposition.
As part of a formal written objection to the plan, Mr Brophy told the appeals board that "the proposed height and density of these buildings is not in keeping with the surrounding area".
"The elevation is at odds with the character of other residential properties," added Mr Brophy, who is currently seeking to retain his seat in Dublin South-West.
"The proposed building height does not respect the natural gradient and topography of the area."
Making the objection also on behalf of Fine Gael councillor Baby Pereppadan, Mr Brophy said: "I fully support increased housing and the provision and redesignation of areas for additional housing.
"However, at the heart of all proposals must be a balance between existing community and the proposed new development.
"Over-development, which in the long term will be damaging to both existing and the new community, is never acceptable," he added.
A submission from South Dublin County Council said it would not be consistent with the Fortunestown Local Area Plan in terms of density, building height and unit mix.
However, the appeals board granted planning permission after concluding the proposed development would not seriously injure residential or visual amenities, or of property in the vicinity. It ruled it would also be acceptable in terms of pedestrian and traffic safety and convenience.