The Dublin Port company will be renewing attempts to reclaim land from Dublin Bay to cope with a projected doubling of trade by 2040.
An Bord Pleanála turned down permission for a 52-acre infill at the eastern end of the north port area last year on environmental grounds.
But the port company today announced a period of public consultation on options to expand the port's capacity, saying that a total of nearly 100 acres may be required.
The options included a refined expansion plan for the area refused by An Bord Pleanála, as well as reclaiming land at the south docks at Poolbeg and infilling part of the existing north port area.
The company also says it needs deeper berths to cope with the increasing size of ships. It suggests dredging along the North Wall and rebuilding that quay to provide berths for cruise ships.
It is also proposing to dredge the Alexandra basin in the northern port area.
Dublin Port company chief executive Eamonn O'Reilly pointed out that port volumes previously quadrupled between 1980 and 2010.
The figures started to grow again last year following the downturn and even with an estimated growth of just 2.5% a year, this would mean trade doubling to 60m tonnes by 2040.
A period of public consultation on the options is due to begin with port customers, local residents and the city council until the end of May and a master plan is to be drawn up by the end of the year.
Minister for Transport Leo Varadkar today welcomed the consultation initiative, saying the smooth running of Dublin Port is vital to the national economy.
The previous expansion plan was opposed by environmentalists, residents in the Clontarf area who feared it could cause flooding, and Dublin City Council, which said it could interfere with amenity plans for Dublin Bay.
An Bord Pleanála refused the expansion on grounds that it could interfere with an area covered by the EU Bird Directive.
Dublin Port already handles half of the country's imports and exports.
