An Bord Pleanála has given permission for the next phase of Dublin Port's €320m masterplan to proceed, subject to conditions.
The project includes the development of a new roll-on roll-off (RoRo) jetty, the lengthening of an existing river berth and the redevelopment of a deep-water container berth.
A new public "heritage zone" at the east end of the port with a structure that will have a viewing deck and a small performance space below is also included in the plan.
"The proposed development in the operational phase will give rise to impacts which are positive," the planning board said in its decision.
"It will facilitate the completion of a single unified Ro-Ro terminal and enhanced Lo-Lo facilities facilitating the removal of capacity constraints within Dublin Port, thereby enabling projected economic growth through increased capacity and improved port infrastructure to facilitate larger vessels."
However, the Docklands Business Forum said the decision "beggars belief".
It said it would consolidate the port's monopoly on the island, marginalising regional ports in the process.
It claimed the decision ignores the reality of Brexit and will greatly damage Ireland's most successful urban regeneration.
The forum also thinks the development will put a strain on local infrastructure adversely impacting the lives of those living and working in Docklands.
The MP2 Project development represents the second stage of three contained in the port's Masterplan 2040.
The port has argued that the redevelopment is needed because of the level of future projected demand and because it will take 15 years to complete the work.
If it proceeds, the project will provide extra capacity of almost a third of the projected increase in RoRo and load-on load-off (LoLo) traffic.
Dublin Port also promised that if the plan was approved it would put a €1m trust fund in place to enable Dublin City Council to develop a city farm near the port, as part of a Community Gain initiative.
It also said it would set up a second €1m trust fund for the school closest to the site, St Joseph's Co-Ed primary school in East Wall.
Under the decision issued by An Bord Pleanála today, the port can build a new Ro-Ro jetty for ferries up to 240 metres in length.
It can also lengthen existing river berth 50A to provide the container freight terminal with additional capacity to handle larger container ships.
Existing Berth 52 can be reoriented, while Oil Berth 3 can be future-proofed as a deep-water container berth for the Container Freight Terminal.
A consolidation of passenger terminal buildings, demolition of redundant structures and buildings, removal of connecting roads and a re-organisation of access roads will also be allowed.