South Dublin County Council has announced 500 new homes will be built in Tallaght.
The Killinarden site is one of the last available areas within the council bounds.
It will feature 300 affordable units, with a mix of private and social housing too.
Councillor Louise Dunne proposed keeping the land in public ownership, but was defeated:
"We believe it should have been all affordable and social. We don't believe there should any private (houses) on it.
"We have enough private developments going ahead in Tallaght," she added.