One of the city's most secret sites is to be opened up under plans for 1,200 new homes on the grounds of the Central Mental Hospital (CMH).
Planning permission for the mix of private, social and affordable homes will be lodged within a year and construction is due to start in 2022.
The development will bring into public view a site three times the size of the Aviva Stadium that has been hidden behind a 5m high wall for 170 years.
Irish and international experts will team up on the project, which has been in the offing for nearly a decade.
Their task is to come up with a scheme that will open up the site and transform famine-era buildings into housing.
The original Victorian hospital shares 11 hectares of grounds and gardens with an array of more modern facilities.
A team of experts will aim to convert as much of the old structures as possible but build from scratch on other parts of the site.
Irish firm Reddy Architecture & Urbanism will work on the project, along with international design consultancy Tyrens, and other Irish companies.
The Land Development Agency (LDA) announced its appointment while setting out an ambitious timetable for the €400m project.
If the green light is given, construction will begin in 2022. The project will go directly to An Bord Pleanala for consideration under the Strategic Housing Development provisions.
CMH cares for psychiatrically ill prisoners, as well as people charged with a serious criminal offence but deemed too ill to plead, as well as those tried for serious crimes but found not guilty by reason of insanity.
Patients and staff remain on site as they await transfer to a new facility on the site of the former St Ita's Psychiatric Hospital in Portrane in north Co Dublin.
Work at Portrane is nearing completion and the move is expected to take place this year.
In the meantime, the LDA said it had access to the Dundrum site for surveys and evaluation work "with due regard for the sensitivity of the CMH's operations".
LDA chief executive John Coleman said the opportunity to work on the unique site was exciting.
"We plan to transform the Dundrum and Windy Arbour area with a landmark sustainable and inclusive new neighbourhood of in excess of 1,200 new homes, incorporating period buildings and mature landscaped grounds," he said.
The LDA's job is to find State-owned lands for 150,000 new homes over the next 20 years.