“Ready meals have been the most affected as they have an eight-day shelf life so any wait is more likely to have an impact,” said Tesco CEO, Ken Murphy.
“Some processed meat and some citrus fruit has also been impacted, but it is important to stress that our availability in the Republic and Northern Ireland is strong and is very strong in the mainland UK. We see this as a challenge at the moment, but not a crisis.”
He added: "Inevitably there are … teething issues that you would expect with any new process that’s been set up at relatively short notice."
This week the British Retail Consortium, the trade body which represents the supermarkets, told MPs that current trading arrangements with the EU were “pretty much unworkable” and called for urgent changes to arrangements for goods heading into Northern Ireland before full border checks are implemented on 1 April.
New trading arrangements were not published in full until 31 December, just a day before businesses had to implement them.
Commenting on overall disruption, Stormont’s agriculture minister Edwin Poots said Nothern Ireland’s government needs to act to avert a “major crisis” in the food supply. Mr Poots said schools and hospitals were in danger of running out of food because of disruption caused by new bureaucracy.
“[This] is an outrageous situation that we in Northern Ireland have been put in as a result of the protocol negotiated between the UK Government and the European Union,” Mr Poots told BBC Radio Ulster.
Meanwhile, Mr Murphy's comments come alongside the latest figures which revealed record Christmas revenues for the UK’s biggest supermarket chain.
Like-for-like sales rose 6.1 per cent in the 19 weeks to 9 January. Online sales grew by more than 80 per cent as staff delivered more than seven million Christmas orders.
Large stores saw sales grow strongly as customers favour bigger but less frequent shopping trips during the pandemic.
Tesco sought to reassure customers about levels of stock, saying that "comprehensive preparations and our strong relationships with suppliers" have resulted in strong levels of availability during the Brexit transition period.
Solid sales figures were offset by the rising cost of the pandemic which Tesco puts at £810m this year, up £85m from its previous forecast.