There were food shortage warnings and the pound dropped after French ports shut to UK outbound freight in what business leaders said was a foretaste of a no-deal Brexit.
On Sunday France banned lorries carrying freight from the UK amid fears over a new mutant coronavirus strain.
Within 24 hours it has caused chaos among supply chains.
Manufacturing NI described events following the port closure as "very, very serious days, and the potential in 10 days to make life for importers and exporters extremely difficult".
And retail chief Aodhan Connolly said the restrictions have illustrated the impact a no-deal Brexit could have on supply chains.
Meanwhile, Sainsbury's said fruit and vegetable shortages will be evident on shelves in the coming days, with one NI wholesaler telling the Belfast Telegraph that it had been advised to stockpile.
Mr Connolly, director of the Northern Ireland Retail Consortium said: "It does go to show the importance of a free flow of goods in from the EU and GB to Northern Ireland and again why it is so important for both sides to agree a Free Trade Agreement."
And although he said that "Christmas dinners would be safe" from the border drama, a spokesman for grocery giant Sainsbury's said: "If nothing changes, we will start to see gaps over the coming days on lettuce, some salad leaves, cauliflowers, broccoli and citrus fruit - all of which are imported from the continent at this time of year."
Northern Ireland fruit and vegetable wholesale supplier Brian Whitten of Whittens told the Belfast Telegraph that he has been told by his supplier to stockpile tomorrow ahead of an anticipated shortage on Wednesday.
Stephen Kelly, chief executive of Manufacturing NI, said: "A speedy resolution is required as each day of disruption now will cause several days to unwind and that leads us in to and over the Brexit cliff edge which remains very possible come New Year's Day."
He said: "Manufacturers have been experiencing difficulties for some weeks as ports in the south east of England have been congested, container ships turning and heading to EU ports and drivers reluctant to travel from Europe to the UK due to fears about getting parked up.
“For now, supply chains are holding up and issues seem to be concentrated to getting goods out to markets. Stresses in Holyhead in the past week have also caused difficulties but seem to be easing.”
Yesterday the UK and French governments were in talks to resume activity across the Channel, with measures being considered including the possibility of testing French nationals to allow them to return from the UK.
But the disruption to normal activity had the effect of spooking the money markets by previeiwing the immediate impact of a no-deal Brexit.
The FTSE 100 blue chip index had fallen by more than 1.7% when trading finished yesterday and companies including British Airways owner IAG and engine maker Rolls-Royce took heavy hits. The FTSE 250, which is generally made up of UK-focused businesses, took a heavier fall and was down 2.11%.
Sterling fell against the dollar and euro, down 0.42% and 0.45% respectively, after minor improvements later in the session. A pound was worth 1.334 dollars and 1.091 euros.
British Airways owner IAG and easyJet were among those hit hardest, with shares down 7.2% and 8% respectively. Neil Wilson, financial analyst at Markets.com, said: “It’s been a very rough start to the Christmas week for the pound, as the lack of a Brexit deal and the closure of key freight routes to Europe knocked sentiment. Brexit talks continue but key sticking points remain, whilst several European countries have blocked travel from the UK due to a mutant strain of the coronavirus rife in the south-east of England.”
He warned that the pound could see a “severe downside shock if there is no deal by Christmas”.
To ease pressures on the freight industry, Stena Line has fast tracked the introduction of its additional Rosslare to Cherbourg freight ferry service. The service will launch today, ahead of its original date of January 4. The freight-only Stena Foreteller will double the freight capacity to 12 weekly crossings connecting Rosslare and Cherbourg and up to 240 sailings per week throughout the Irish Sea region.