Excessive overshadowing of some existing homes by the proposed Spencer Dock development was one of the main reasons given by An Bord Pleanala for its refusal to grant permission for the major part of the scheme.
The board also attached 17 conditions to its permission for the 2,500-seat national conference centre and parking spaces and bus, coach and taxi set-down areas.
In its nine-page judgment on Ireland's largest urban design project, the board refused permission for the rest of the proposed £1.2 billion high-rise development, which included two hotels of 10 and 12 storeys, nine office buildings up to 22 storeys and 11 apartment blocks.
Dublin Corporation had granted full permission last August for the conference centre and one office block, but only outline permission for the rest of the site, which it also scaled back from six million to 4.6 million square feet.
The board's decision followed a three-week oral hearing this year by three inspectors. It detailed six reasons for refusing permission to the bulk of the plan.
Citing the Dublin City Development Plan, it said the proposed development's "scale, bulk and mass and campus-style layout. . .would constitute an inappropriate urban form of development for Dublin" and would "materially contravene" the plan.
It found the proposed development premature in advance of decisions on aligning a crossriver rail link to the east of the Loop Line, as well as resolving the role of the Spencer Dock rail station in the context of the city's transportation framework.
A further reason was the harm to "visual amenities" from Fitzwilliam Street - part of a conservation area known as Dublin's "Georgian Mile".
Regarding the effect on some homes on the edge of the development, the decision said the proposed buildings "by reason for their height, design and massing, would result in excessive overshadowing, overlooking and loss of daylight."
One of the 17 conditions states that the consortium will have to contribute £200,000 to Dublin Corporation towards road construction and improvement works on the site.
Another condition is that the national conference centre be moved at least nine metres eastwards to make way for a park. The consortium behind the proposal - Treasury Holdings, the docklands businessman, Mr Harry Crosbie, and CIE - yesterday said its design team would study the decision and prepare a revised planning application.
Its chairman, Mr Dermod Dwyer, said he was pleased the board had endorsed the conference centre, designed by the internationally renowned Irish emigr e architect, Mr Kevin Roche.
"There are obviously going to have to be trade-offs, perhaps between the amount of built land and open space, but for definite this consortium is going to develop Spencer Dock," he said.
The full text of the decision is on: www.pleanala.ie