Ireland is increasing direct freight shipments to and from mainland Europe as businesses move to bypass potential snarl-ups at British ports after Brexit.

Many companies ship goods between Ireland and continental Europe via Britain, with about 150,000 lorries passing through what is known as the UK “land bridge” each year. Doing so via swift sea crossings between Dublin and Holyhead and then Dover to Calais provides the fastest route to market for traders in perishable and high volume goods.

But the end of the UK transition period on December 31 means truckers now face new checks as they leave EU territory to enter Britain from Ireland or France and then return to the bloc after passing through the UK. This has prompted anxiety about paperwork at ports and potential chaos on the busy Dover-Calais route.

Such risks were highlighted shortly before Christmas when France closed the Dover-Calais crossing due to concerns about a highly transmissible new coronavirus strain, leading to huge tailbacks in which hundreds of Irish truckers were left stranded in Britain.

Micheál Martin, Irish prime minister, said the disruption pointed to the need for “alternative routes” to the land bridge even with a Brexit deal in place.

The delays at Dover prompted a surge in demand for such services, leading ferry operator Stena Line to double pre-Christmas capacity on its direct freight link between Rosslare in south-eastern Ireland and the French port of Cherbourg.

Although sailing times are longer on direct sea crossings to the continent, worries about Brexit had already spurred many Irish exporters and importers to make use of increased capacity on such routes.

“There is good demand for it,” said Simon McKeever, chief of the Irish Exporters Association, a trade body.

“There is definitely for some time been a desire to seek out an alternative to the land bridge and we are seeing members looking to avail of more direct shipping routes to the continent, to the extent that some companies are having difficulty booking space on the inward-bound journey from France early in the new year,” he said.

The Irish Maritime Development Office, a government body to develop and promote shipping, has advised exporters and importers to examine alternatives to the land bridge since 2019. Direct continental roll-on roll-off and lift-on lift-off routes from Ireland are the “fastest-growing routes” in recent years, it added.

Several new direct freight services have been introduced since 2018 — linking Ireland with ports in France, the Netherlands, Spain and Portugal — despite the availability of swifter roll-on roll-off capacity on the land bridge.

Senior figures in Irish transport say the introduction on January 2 of a new roll-on roll-off service between Rosslare and Dunkirk in France, has the potential to be a game-changer, with six sailings a week in each direction.

DFDS, the Danish operator of the new service, aims to displace a significant portion of the 150,000 shipments on the land bridge.

“We obviously need to eat into that to a relatively large extent,” said Torben Carlsen, chief executive of DFDS. “We probably need 40,000-50,000 of those movements to make this route viable.”

Glenn Carr, general manager of Rosslare port, said freighters had booked “very strong loads” in both directions on the Rosslare-Dunkirk route as the service started at the weekend. Similarly, Stena Line said its first post-Brexit-transition sailing to Cherbourg from Rosslare was sold out.

The Rosslare-Dunkirk sailing takes 24 hours, about six hours longer than travelling between Dublin and Calais via Britain. But going via Dunkirk provides more time on the road after arriving in Europe because truckers will not have been driving for a day. “Their goods will not leave the EU. In addition, the drivers will be rested when they arrive,” Mr Carlsen said.

By contrast, the drive through the British land bridge limits truckers’ hours on the road after they arrive in Calais.

Perennial, an Irish freighter specialising in direct services to the continent, had already moved to boost its capacity to meet a sharp rise in demand before the end of the UK transition period on January 1.

Chris Smyth, Perennial’s commercial director, said: “A lot of it is being driven by the big supermarket chains. The multiples are putting pressure on the fruit importers because they need continuity of supply. On the export side, it’s big Irish meat and dairy producers. Because it’s food product, they want to avoid both the customs documentation and any [sanitary and phytosanitary] checks.”

Mr Carr at Rosslare said supply chain changes in the Brexit era have driven a big rise in direct freight traffic to the continent. “We were down to three sailings per week direct to Europe about 18 months ago. From January we go to 11 direct and from March we go up to 13,” he said.

“What it means is a quadrupling of direct services to mainland Europe and that’s attributable to the market demand.”