Up to a fifth of workers in companies are having to self-isolate after receiving a notification from the NHS Covid app, threatening cuts in production of goods.

Business groups and unions told the PA news agency that the problem had escalated this week, leading to pleas for the Government to step in.

There are calls to bring forward the August 16 date where the fully vaccinated will not have to self-isolate if they come into contact with someone with Covid-19.

The number of people notified by the app in England and Wales recently passed 500,000 in a single week.

This is a problem that has escalated significantly over the last week with more and more companies being affected by isolation

Stephen Phipson, chief executive of manufacturing organisation Make UK, said: “This is a problem that has escalated significantly over the last week with more and more companies being affected by isolation, with not just an impact on production but a hit to actual shipments of goods going overseas.

“This is an increasingly serious issue affecting companies of all sizes and sectors. There is now an urgent priority for Government to bring forward the August date given the likely impact of restrictions being lifted next week.”

Small and large companies are being hit by staff shortages of up to 20%, PA understands.

Car giant Nissan has been affected at its plant in Sunderland and it is believed that other carmakers, including Rolls-Royce could also have to make changes to production schedules to deal with the problem.

If the UK workforce situation deteriorates further, companies will be forced to start shutting down production lines altogether

A spokesman for the British Meat Processors Association said: “We’re hearing reports from some members that between five and 10% of their workforce have been ‘pinged’ by the app and asked to self-isolate.

“This is on top of the desperate shortage of workers that the industry is already suffering. As a result, companies are having to simplify down their range of products to compensate for key skills being removed from their production lines.

“If the UK workforce situation deteriorates further, companies will be forced to start shutting down production lines altogether.

“It’s for this reason that we’ve been calling on the Government for months to add butchers to the Shortage Occupation List, which would allow the industry to temporarily fill these growing vacancies with overseas workers until the current crisis has passed.”

Frances O’Grady, general secretary of the TUC, said: “Staff shortages will only get worse unless people are kept safe at work.

“The Government urgently needs to toughen its confusing and inadequate back-to-work safety guidance – starting with making masks a legal requirement on public transport and in shops.

“If we are to stop Covid-19 ripping through workplaces, workers must be able to afford to self-isolate. Government must urgently raise sick pay to the level of the real living wage and make sure everyone can get it.”

The Rail, Maritime and Transport union warned that the surge in people being pinged with self-isolation instructions will increase on Monday due to the Government’s “confused and conflicting” messaging on wearing masks on transport services.

‎General secretary Mick Lynch said: “RMT warned earlier this week that the Government’s botched handling of continuing Covid protection measures on public transport from Monday would have dire consequences and the sheer incompetence of those calling the shots will see a surge in workers pinged with a self-isolation instruction next week.

“Even at this late stage the Government, the train operators and the bus companies should issue a clear, legally backed instruction that levels up the rest of the UK up to the safety standards that will remain in force in Wales and Scotland.”

Urgent action is needed... such as a change to the sensitivity of the NHS Test and Trace App or bringing forward the 16 August target date for exempting fully vaccinated adults from self-isolation

Mike Hawes, chief executive of the Society of Motor Manufacturers and Traders, said, “Like many other sectors of the UK economy, automotive manufacturers and suppliers are being impacted by the growing number of coronavirus cases as restrictions are eased.

“The industry has taken every step to make premises Covid safe, but with transmissions rising outside the workplace, and self-isolation rules preventing staff from working, staff shortages are putting production at risk and undermining the sector’s recovery.

“Urgent action is needed to mitigate this impact, such as a change to the sensitivity of the NHS Test and Trace App or bringing forward the 16 August target date for exempting fully vaccinated adults from self-isolation.”

Tim Morris, chief executive of the UK Major Ports Group, said: “Port operators have been seeing rocketing numbers of staff having to isolate after being contacted by the NHS Covid app and from household isolation requirements.

“Most of these workers have received one vaccination already with many already double jabbed. We’re seeing some port operators with 10% of their workforce having to isolate and worrying trajectories at other major UK gateways.

As cases increase, more rail employees could be pinged by the NHS contact tracing app and be asked to self-isolate

“In many cases this is the worst absence situation that ports have experienced through the whole pandemic.

“Ports have done a great job of remaining open as the gateways for 95% of the UK’s trade throughout the pandemic, but we can’t isolate ourselves totally from the broader trends in the population.

“What we need are protocols that better reflect the vaccination status of key workers.”

Robert Nisbet, of the Rail Delivery Group, said: “Rail companies are working hard to keep passengers safely on the move as restrictions ease and more people travel to work or to see friends and family.

“As cases increase, more rail employees could be pinged by the NHS contact tracing app and be asked to self-isolate.

“While train companies are doing everything they can to minimise any disruption, there may be an impact on services so we are asking people to check before they travel using app alerts which were upgraded during the pandemic as part of our safer travel pledge.”

A Rolls-Royce Motor Cars spokesman said the company was running at full production, adding: “We operate a two-shift system and every car is hand-built to customer order.

“We are extremely concerned at the number of employees at our manufacturing plant who have been forced to self-isolate after being notified by the NHS Test and Trace App.

“We are approaching a critical point – it will be necessary to reduce our two shifts to one if numbers of self-isolations continue to rise, effectively halving production. This would be deeply detrimental to our customers’ expectations and our business.”