Northern Ireland businesses have called for an extension of the Brexit transition period in the region, warning they “simply will not be ready” for the mandatory border checks on 1 January.

They say they are the “rope in a tug of war” between the UK and the EU and warned of a “huge black hole” in information and a “disconnect” with Westminster and Brussels over the reality of Brexit checks kicking in 43 days’ time.

“There is a responsibility on the EU as well as the UK” to make sure the Northern Ireland protocol works, Stephen Kelly, the chief executive of Manufacturing Northern Ireland, told MPs.

While Brexit trade talks remain in the balance, the Northern Ireland protocol, which will involve border checks down the Irish Sea, is due to kick in at the end of the transition period – deal or no deal.

Kelly called for pragmatism over cross-border shopping. “Selling a lasagne at an Asda in Strabane that might make its way to Donegal is not going to pollute the entire single market,” he told the Brexit select committee.

MPs were also told that, if the protocol were applied to the letter, a simple ham and cheese sandwich made in Britain and sold in Belfast would need two health certificates to get through the border control posts.

These issues were supposed to be ironed out by the UK-EU joint committee chaired by Michael Gove and Maroš Šefčovič but Northern Ireland traders have had “no conversations with anyone” about the at-risk goods, said Kelly.

Kelly said Northern Ireland could be a recurring nightmare for the EU unless they made the protocol work and said the bloc needed to be “generous in spirit” and grant an implementation period for the protocol.

“The EU need to make it work,” he said but they needed to get businesses to “make it stick”.

“We are more than a pawn in the game and say that’s a tug of war and we’re the rope and that rope is sadly being stretched,” he warned.

The EU will warn of a worrying lack of progress as leaders meet at a summit via videoconference on Thursday.

EU sources said Charles Michel, the European council president, would give a downbeat public assessment of the troubled talks. The two sides remain stuck on EU access to UK fishing waters, the workings of a mechanism to maintain environmental, labour and social standards over time and the details of how disputes will be resolved.

After a briefing by the EU’s chief negotiator, Michel Barnier, on Wednesday, the European commission vice-president Valdis Dombrovskis said there remained “substantial work to do”. “I will not start putting specific deadlines: this week, next week. We have seen many deadlines come and go but there’s one deadline which we’ll not be able to move – 1 January,” he said.

A senior EU diplomat representing a member state said the commission had a responsibility to make further preparations for a no-deal outcome given the lack of progress in the talks. “I don’t have the impression that there is much progress,” the diplomat said. “It is time to say: we must now come up with contingency measures, 1 January is getting close. We need a safety net. Of course this sends out a political signal. But we have a business community that we want to tell in good time what to do. ”

Kelly’s concerns over cross-border trade were echoed by Aodhán Connolly, the director of the Northern Ireland Retail Consortium, who said: “We are hugely worried” that the retail sector would not be ready as it was being asked to make “structural changes that would normally take two years” in six weeks. “We need an implementation period,” he added.

Victor Chestnutt, the president of the Ulster Farmers’ Union, told MPs it was only beginning to sink in now that farmers in the region would be treated differently to those in the rest of the UK, and that “all farmers” would need special paperwork to import secondhand machinery and agri-products including grass seed and seed potatoes.

At a recent webinar only five out of 140 farmers said they knew about the paperwork.

There is “a huge disconnect between government and farmers on what we need to do”, Chestnutt said. “With six weeks until the day, it feels like we’re going forward with both arms tied behind our back and a blindfold on. You know if you give us clarity and give us time, we will get through it. But we do need an implementation period or honeymoon period.

“We have a transition period but we do not know what we are transitioning to with six weeks to go,” he added.

The committee heard there was not enough time to make the mandatory changes to food labelling. There were also concerns that the agrifood sector did not know if it faced a Brexit cliff-edge on 1 January for its thriving cross-border operations.

The shadow Northern Ireland secretary, Louise Haigh, told parliament during an urgent question that the “reckless approach” of the government meant “thousands of businesses still do not know the bare basics of how they will trade with Great Britain in just six weeks’ time”.

About £2.6bn in agrifood produced in Northern Ireland goes to Great Britain and 60% of that transits through Dublin Port, the committee heard.

“It’s a cyclical, circular, integrated supply chain across these islands,” said Connolly.

The committee heard that no deal would block this trade on the island of Ireland with data showing a cottage pie has “nine border movements” and Baileys Irish Cream had five such border crossings. “If that [model] is removed it means means delays, less choice, less freshness.”

The Northern Ireland minister Robin Walker told parliament the government was pursuing a “flexible” approach and the protocol was “on track” to be delivered on time.

A government spokesman said that “further measures to support agrifood traders will be announced shortly” and that it was “working to resolve all outstanding issues for supermarkets and other traders through the joint committee”.