Elderly care home residents have been categorised “en masse” as not requiring resuscitation, in a strategy branded unacceptable by the healthcare regulator.

People in care homes in Hove, East Sussex and south Wales are among those who have had “do not attempt resuscitation” (DNAR) notices applied to their care plans during the coronavirus outbreak without proper consultation with them or their families, MPs and medical unions fear.

Care homes in Leeds have reported that district nurses have been asking them to “revisit do not resuscitate conversations with people who said they didn’t want them” and a care worker in Wales told the Guardian that after a visit from a GP, all 20 of their residents had DNAR notices attached to their plans.

An NHS health board in another area of Wales has apologised this week after a GP surgery near Port Talbot recommended that patients with serious illnesses complete DNAR forms.

DNAR notices are a common part of care plans and many people wish to have them in place because, in the event of cardiac arrest, attempts to resuscitate can cause serious trauma, including broken bones. But the Care Quality Commission and other medical bodies are so concerned about the blanket application of the notices that it has issued a warning to stop.

“It is unacceptable for advance care plans, with or without DNAR form completion, to be applied to groups of people of any description,” the notice states. “These decisions must continue to be made on an individual basis according to need.”

The Royal College of General Practitioners said GP practices have written to care homes about updating care plans in the light of Covid-19, which appears to be many times more fatal in the oldest people than younger generations. It said there had been confusion in some care homes about what they were being asked to do.

Peter Kyle, Labour MP for Hove, said care homes in his constituency were issuing DNAR notices “en masse”, saying that in one home, 16 of the 26 residents signed DNARs under instruction from a GP. He said all appeared to be planning as though residents over the age of 75 would remain in their homes if they contracted Covid-19 rather than being admitted to hospital.

“They are to die in the homes, which is why they are issuing DNARs,” he said. “The DNARs are important because they are not equipped to intervene and ventilate them.”

Kyle is calling for urgent testing for care home workers, as they are the most likely cause of the virus’s arrival in a property.

“If government doesn’t start testing care home workers in a matter of days, it is knowingly allowing people in care homes to get infected and die,” he said. “Rather than preventing harm, our system is actually infecting them. This is something that is going to haunt our country.”

As the virus spreads through care homes, providers have warned that they may lose around half of their staff due to illness or self-isolation, putting residents further at risk.

Alex Sobel, MP for Leeds North West, wrote to Boris Johnson on Wednesday calling for immediate testing, “or we will see lives lost that did not have to be”. He said that not one of the care facilities his office contacted on Wednesday had had testing offered to staff or residents, even those who were displaying symptoms, and that some homes still had not received consignments of basic protective gear that was promised by the government by the end of last week.

A coalition of care industry bodies in England, Scotland and Wales has meanwhile asked the government to allow furloughed workers in industries like hospitality and catering to fill the vacancies by allowing them to work as carers and still receive their 80% payments from their other job.

It emerged on Tuesday that a Merseyside care home, Oak Springs, is operating with just a quarter of its normal staff amid an outbreak of the virus. Paula Bark, the local MP, confirmed that two residents had died while displaying symptoms of coronavirus, three more were in hospital, and of the remaining 66 residents, 42 were showing symptoms.