Boris Johnson has been accused of “screwing over” Northern Ireland amid widespread disruption following the end of the post-Brexit transition period.

DUP MP Ian Paisley said the prime minister’s Brexit settlement has “ruined trade” in Northern Ireland and that it was an “insult to our intelligence” to suggest the issues are simply “teething problems”.

Johnson was widely accused of “selling out” his DUP allies in 2019 by agreeing to place Northern Ireland in a special zone where it has to follow EU rules in many areas to keep an invisible border with the Republic.

The move was a departure from Theresa May’s approach, which would have kept Northern Ireland more in line with the rest of the UK, but was rejected by Tory MPs because it tied the whole country closer to the EU instead. 

Since the Brexit transition period ended on December 31 and the UK left the European single market, Johnson’s Northern Ireland protocol arrangements have caused disruption for firms trading with Northern Ireland and the EU.

Labour’s shadow Northern Ireland secretary Louise Haigh described “empty supermarket shelves, lorries from Northern Ireland stuck in Britain or returning empty, and the unnecessary checks on everything from guide dogs to people moving house”.

At prime minister’s questions in the Commons, Johnson was asked to invoke so-called “last resort” measures in the protocol to allow the UK to take unilateral action to solve the problems.

The PM said: “At the moment goods are flowing effectively and in normal volumes between Great Britain and Northern Ireland. So far no lorries have been turned back.

“Yes of course there are teething problems and what I can confirm to him is that if there are problems that we believe are disproportionate then we will have no hesitation in invoking Article 16.”

Later, Paisley criticised Johnson’s claim that empty supermarket shelves in Northern Ireland are down to “teething problems” and called for a grace period to allow firms to adapt to EU certification rules to be extended for a year beyond March.

During an urgent question to Michael Gove on the situation, he told MPs: “What did we do? 

“What did we do to members on those (Tory) benches over there to be screwed over by this protocol?

“Ask your hearts, every single one, what did we do?  

“Because what has happened to this protocol is it ruined trade in Northern Ireland and it is an insult to our intelligence to say it is a teething problem. Tell that to my constituents.” 

Gove admitted the government’s Brexit settlement “undoubtedly generates challenges as well as providing solutions”. 

The Cabinet Office minister claimed there had been “no significant queues” at borders and that “supermarkets are now generally reporting healthy deliveries of supplies into Northern Ireland”.

Gove also promised to do more to help companies on the UK mainland understand the Northern Ireland arrangements, to “intensify” engagement with Ireland trade because trade via Dublin ports is “substantially lower than normal”, and said the government was working on “streamlined replacements” to follow the grace period.

The exchanges came as retailers warned that supermarkets in Northern Ireland will face fresh shortages on the shelves unless the EU is prepared to extend the grace period. 

“If we do not find a workable solution for retailers in the next couple of months we do face significant disruption in Northern Ireland,” British Retail Consortium director Andrew Opie told the Commons Brexit committee.

Opie said that supermarkets which exported to the Republic of Ireland had found the system was “unworkable” as far as their supply chains were concerned.

“That is why we need to think about Northern Ireland. We should not just be trying to apply the same processes that apply to the EU into Great Britain-Northern Ireland,” he said.

“Sending a lasagne from Great Britain to the Republic of Ireland is so complicated. You have to have authorisation going up through the chain, the vet at the end has to sign it off and he has to see all the authorisations.”

Food and Drink Federation chief executive Ian Wright warned that without changes to the Brexit arrangements, the industry would have to rethink its all of its supply routes, leading to increased costs and delays for trade with both Northern Ireland and the EU.

He said that one international supplier had found that the paperwork for a consignment moving from the UK to the EU which would normally have taken three hours to complete had so far taken five days – and they were still working on it.

Wright also expressed concern about the potential for delays at the Channel ports as the number of lorries making the crossing picked up over the coming months.

“It will get worse. Currently volumes across the short straits are at about 2,000 lorries. They should be around 10,000. So the opportunity for the scale of concerns to rise is huge,” he said.