Dublin county councillors rezoned massive amounts of residential and industrial land against the advice of planners during the 1980s and 1990s, the tribunal heard.
Mr John Gallagher SC, for the tribunal, said councillors rezoned enough industrial land to last between 27 and 100 years, depending on the rate of uptake, during the drawing up of the 1993 plan for Co Dublin.
This was in spite of the view of the planning manager, who told councillors there was a "more than adequate supply" of industrial zoned land in the county to last until "well into the next century".
Mr Gallagher said a neutral observer would have been forgiven for thinking that, given this advice, the councillors would not have rezoned more industrial land. However, the observer would have been wrong.
In fact, local representatives rezoned 1,212 acres for industrial land during the drawing up of the 1993 plan.
At this time, over 4,200 acres were already zoned industrial and 57 per cent of these remained undeveloped. Almost 750 acres of this land had planning permission, counsel said.
The councillors also rezoned another five years' worth of residential housing against the wishes of planners.
At this time, over 1,500 acres of residential zoned land remained undeveloped but had planning permission, and 4,360 acres of residential land had no planning permission.
Planners said there was an ample supply of residential zoned land for "many years to come", but councillors still went ahead and rezoned almost 1,000 acres, the equivalent of five years' supply.
The rezonings radically altered the plans laid in the 1970s for Dublin's expansion to the west.
This envisaged that most growth would take place in three new towns, Tallaght, Lucan/Clondalkin and Blanchardstown.
Mr Gallagher warned that no one listening to the evidence heard at the tribunal should reach a conclusion until all the evidence had been heard and, in particular, until rebutting evidence had been taken.
He warned against reaching "premature judgment" before that point had been reached.
