The Dublin Airport Authority (DAA) today warned it risked missing the deadline to have the much needed new Terminal Two up and running.
Due to be open by the end of 2009, it will take nearly two and a half years to build and make ready for passengers.
Up to 10 million people are expected to use it each year.
An Bord Pleanala confirmed it has targeted August 2 for a decision on the controversial €170m project, but the DAA called for planners to make an early ruling.
"The new terminal has a two-year construction time-frame and subsequent five-month commissioning schedule, which by any standard is extremely tight," DAA chairman Gary McCann said.
"Consequently, we need to have planning clarity by the end of June in order to begin preliminary construction activity by mid-July and deliver an operational facility before the end of 2009."
An Bord Pleanala said notices of the target date for a decision on T2 were issued to all parties on April 5.
"The DAA fully appreciates An Bord Pleanala's very heavy workload and the care it has taken in processing the T2 planning appeal to date," Mr McCann said.
"However, the company had expected an outcome to the appeals process within six to eight months of obtaining planning permission last October.
"We must hope, given An Bord Pleanala's many commitments, it is in a position to prioritise its deliberations on T2 — given Dublin Airport's strategic importance for millions of passengers and the overall economy."
The DAA lodged a planning application in August 2006 and secured planning permission a few months later in October, but that decision was appealed.
Seven parties have lodged objections to the T2 plan and a number of others have made observations to planners. The objectors include Ryanair, An Taisce and the Portmarnock Community Association.
An oral hearing, which lasted for three weeks was also held in April.
Issuing results for last year, the DAA revealed total profits of €166m for 2006, with returns boosted by the sale of the Great Southern Hotels Group for €125m.
Combined passenger numbers at Dublin, Shannon and Cork Airports rose by 14 per cent last year to 27.8m with Dublin Airport taking the biggest share recording 21.2m people travelling through.