LONDON (BLOOMBERG) - The UK government is rolling out daily Covid-19 testing to allow workers in supermarket depots and food manufacturers to avoid self-isolation, amid concerns that mass staff shortages are threatening crucial supplies.

As many as 10,000 workers at about 500 key sites will no longer need to self-isolate for 10 days if they come into contact with a positive case, Environment Secretary George Eustice told broadcasters on Friday (July 23).

Separately, other critical sectors in England including energy, waste, water, border control and emergency services will be able to replace self-isolation with daily testing for a limited number of workers who are double-vaccinated.

Businesses from stores to car factories have reported disruption after hundreds of thousands of people were contacted - or "pinged" - by the National Health Service coronavirus app and told to isolate.

Latest figures from the NHS showed 608,000 people were notified last week, up from 356,000 two weeks before.

Images published in newspapers showed empty supermarket shelves on Thursday, leading ministers to express concern over potential shortages of goods.

The government appealed to the public not to panic buy food.

Mr Eustice said he received assurances from supermarket leaders that the problems are not widespread.

"We have a highly resilient food supply chain," he said in an emailed statement. "There are sufficient food supplies in the system and people can and should shop as normal."

The food workers program will only apply to depots and manufacturers and not supermarkets themselves, because this would involve "many more people and we still want to maintain the test, trace and isolate system", he told Sky News.

Under separate government guidance, named workers in "specifically approved workplaces" who are fully vaccinated will be allowed to continue working after being identified as a close contact of someone with Covid-19.

Their employers must apply to the government and demonstrate that the person works in "critical elements of national infrastructure" and their absence would have a "major detrimental impact on the availability, integrity or delivery of essential services," or impact national security or defence.

The process is intended to run until Aug 16, when fully-vaccinated people who have been in close contact with Covid-19 cases will be exempt from isolating.