A rise in numbers of food supply workers being forced to self-isolate is being blamed for empty supermarket shelves.
Shoppers across the UK have been alarmed to find shelves and fridges empty.
A surge in workers being alerted by the NHS Covid app on their phones has hit industries hard because workers have to stop at home.
Staff at supply companies, fruit and veg farms and supermarkets are among the thousands being “pinged” when they have been close to someone infected by the coronavirus.
Hundreds of people – in places as far apart as Edinburgh, Devon, Hampshire, London and Liverpool – have posted photographs on social media showing shortages of certain types of goods.
Andrew Opie, of the British Retail Consortium, said: “The ongoing pingdemic is putting increasing pressure on retailers’ ability to maintain opening hours and keep shelves stocked.
“Government needs to act fast. Retail workers and suppliers, who have played a vital role throughout this pandemic, should be allowed to work provided they are double vaccinated or can show a negative Covid test, to ensure there is no disruption to the public’s ability to get food and other goods.
“With community cases soaring, the number of healthy retail staff having to self-isolate is rising fast, disrupting retail operations.”
Even before the rise in pings, food industry chiefs were warning of empty shelves because a shortage of lorry drivers has also delayed supermarket deliveries.
Tesco said the HGV driver shortages have led to 48 tonnes of food being wasted every week.
Many European drivers returned to their home countries both because of Brexit and the three national lockdowns.
Since then others have been off sick with the coronavirus, and the pandemic has created a large backlog in HGV driver tests.
But the BRC said the pingdemic had been a much bigger problem than the driver shortage over the past few days.
Supermarkets are urging shoppers not to panic buy, and some shoppers posted photos of well-stocked shelves, suggesting the shortages were had not reached everywhere.
Some stores said the heatwave had caused fridges and freezers to fail, so they had to be emptied.
Waitrose had notices up apologising for the “limited choice” because of “nationwide supply issues”.
Business ministers have written to major manufacturers emphasising that staff are not legally obliged to isolate if pinged.
Logistics UK, which represents freight owners including supermarkets, estimates about 90,000 HGV driver jobs are unfilled.
The Independent has asked the government to respond.