Dublin Port has said it will not allow congestion of the port to block the Dublin Port Tunnel, the M50 or the M1 in the event of a no-deal Brexit.
It says it will achieve this by making trucks take a u-turn at the port and directing them back up the northbound bore of the Port Tunnel to wait elsewhere until congestion clears.
Chief Executive of the Dublin Port Company, Eamon O'Reilly, said Dublin Port has lost 10 hectares of land in recent months to the State border inspection services to prepare for Brexit checks, and that that has removed the "small bit of buffer capacity" that was available within the port.
Speaking on RTÉ's Today with Sean O'Rourke programme, Mr O'Reilly said it would be "too dramatic to say that we're on a knife edge but it doesn't matter if its down to a Brexit-related issue, or indeed bad weather or any factor, we need to have a mitigation in place that we can ensure that the problems of the Port don't become the problems of Dublin city."
Mr O'Reilly said that the diverted trucks could go to "other areas" where there was some capacity such as where they had originally come from or motorway stops.
He said the port had not done a dry-run on the measures but he said it would be publicising details of their plans in early October.
In the event of checks being applied, he said, there is just 3km of roads within Dublin Port with the capacity for about 250 trucks.