Brexit trigged a major reduction in cargo volumes at Dublin Port in the first quarter of this year, while Covid-19 also hit passenger numbers.
The Dublin Port Company said today that its trade volumes fell by 15.2% in the first three months of 2021.
The main driver was a decline in freight from British ports, which fell by 29% to 160,000 units.
In contrast, trade with EU ports rose by 18% to 158,000 units.
The company said that imports in the three months from January to March fell by 14.4% to 4.7 million gross tonnes and exports declined by 16.6% to 3.1 million gross tonnes.
Today's figures show that imports of new trade vehicles declined by 12.6% to 27,000 units.
Due to continuing reduced transport demand in the economy, imports of petroleum products fell 23.4% to 0.9 million tonnes.
But bulk solids (including agri-feed products, ore concentrates and cement products) finished the quarter 9.9% ahead at 0.5m tonnes.
The Covid-19 pandemic also continued to supress passenger and tourism volumes.
Passenger numbers on ferries (including HGV drivers) declined by 63.2% to 83,000 while tourist vehicles declined by 74.3% to 17,000.
Dublin Port's chief executive Eamonn O'Reilly said it is too early yet to say what the long-term effects of Brexit will be and whether the declines seen so far in 2021 will persist at the same level for the rest of the year.
"With two ferry lines (Irish Ferries and P&O) now operating services both from Dublin Port to the UK and across the English Channel from Dover to Calais, we are optimistic that the landbridge will re-establish itself as a fast and cost effective option for the movement of time sensitive goods to and from Continental Europe in the months ahead," Mr O'Reilly said.
But he added that the dislocation of a lot of volume to ports in Northern Ireland is "worrying".
"Back in 1990, before the Single European Market was established, more than a third of Ro-Ro trade chose services to and from Northern Irish ports rather than use services in and out of Dublin Port," he said.
"We won't get a proper sense until later in the year as to how much of the 29% decline we have seen in GB Ro-Ro trade is due to the new border regimes and whether this dislocation will be a permanent feature for the years ahead or not," he added.
Mr O'Reilly said the only positive thing in the figures for the first quarter is the growth of 18% in Ro-Ro and Lo-Lo volumes on direct services with Continental Europe.
"This confirms that the investment decisions we have been taking in recent years under Masterplan 2040 were correct. It also shows the responsiveness of the shipping market to rapidly provide the capacity needed for the changes in demand patterns which Brexit has caused," he added.
Today's figures show that roll-on/roll-off volumes to and from France, Belgium and the Netherlands increased by 26% in the first quarter while lift-on/lift-off services between Dublin Port and mainland European ports were 18% higher, the statement said.
For decades, Irish traders have preferred to ship goods to the rest of Europe via Britain, taking a short sea crossing to ports in Wales and then a hop to France.
Mr O'Reilly said Dublin Port was optimistic that the so-called UK landbridge will re-establish itself as a fast and cost-effective option in the months ahead.