The home secretary has said she is sorry if NHS staff feel there has been a failure to provide protective kit for those treating coronavirus patients.
But Priti Patel said there were going to be problems during what she called an "unprecedented global pandemic".
The British Medical Association earlier said that NHS staff were putting their lives at risk when treating patients.
The health secretary said earlier that 19 NHS workers had died with coronavirus since the outbreak began.
Speaking at Saturday's coronavirus briefing in Downing Street, the home secretary said: "I'm sorry if people feel that there have been failings. I will be very, very clear about that.
"But at the same time, we are in an unprecedented global health pandemic right now. It is inevitable that the demand and the pressures on PPE and demand for PPE are going to be exponential."
On Friday, Health Secretary Matt Hancock said there was enough kit for everyone and unveiled a plan to address shortages.
He said the government was looking into how NHS staff who had died with the virus had been infected - adding that some may have caught it outside of work.
"But that doesn't take away from the bravery of every single NHS worker," he said, adding that his "heart goes out" to those who have died and their families.
Mr Hancock said he was "particularly struck at the high proportion of people from minority ethnic backgrounds and people who have come to this country to work in the NHS who have died of coranavirus".
"We should recognise their enormous contribution," he added.
Supplies of personal protective equipment (PPE) in London and Yorkshire are at "dangerously low levels", according to the BMA.
Dr Chaand Nagpaul, BMA council chair, said doctors were being forced into a corner and faced "heart-breaking decisions" over whether to carry on without proper protection.
He said: "This is an immensely difficult position to be in, but is ultimately down to the government's chronic failure to supply us with the proper equipment."
A nurse at Watford General Hospital in Hertfordshire, who wanted to remain anonymous, told the BBC he felt unsafe with the level of PPE he had been given.
He said shortages meant those working on wards with coronavirus patients were only being given a surgical mask and plastic apron, rather than a gown covering the whole body.
Last week a nursing assistant who had been looking after coronavirus patients at the hospital died.
"We are scared because we are spreading the virus," he said. "We don't deserve it and our patients even more."
The health secretary said 742 million pieces of protective gear had been delivered so far, saying: "There's enough PPE to go around, but only if it's used in line with our guidance. We need everyone to treat PPE like the precious resource that it is."
Mr Hancock said he was not "impugning anyone who works for the NHS" and "they do an amazing job".
"But what I am reiterating, stressing, is the importance to use the right amount of PPE," he added.
However, Labour leader Sir Keir Starmer said it was "insulting to imply frontline staff are wasting PPE" and the government "must act" to ensure sufficient supplies are delivered.
For several weeks, the government and NHS leaders have insisted there are enough stocks of personal protective equipment (PPE) and that the problem lay in the distribution from warehouses to the front line.
Some hospitals have reported receiving higher consignments of gloves, masks, gowns and aprons. But doctors and nurses have continued to report shortages.
Care homes, pharmacies, GP practices and community health teams feel they are at the back of the queue for equipment to protect staff who may come into contact with patients who have Covid-19.
There has also been confusion over how safety guidelines should apply.
Now Matt Hancock has admitted there are global supply problems and says it is a "herculean effort" to get deliveries to health workers and a "huge task" to keep it going. He set out a series of measures to step up provision of equipment.
He may be given credit for acknowledging the scale of the problem. But NHS and care staff won't take much notice of plans until they are reflected in reality on the ground.
The Royal College of Nursing (RCN) has dismissed any suggestion that healthcare staff have been overusing PPE.
RCN chief executive Dame Donna Kinnair told the BBC no PPE was "more precious a resource than a healthcare worker's life, a nurse's life, a doctor's life".
"I take offence, actually, that we are saying that healthcare workers are abusing or overusing PPE," she told BBC Breakfast, adding that nurses were still telling her they did not have adequate supply of protective equipment.
Meanwhile, the business organisation Make It British said the government had not yet taken up offers from some firms to help manufacture PPE.
The group said at least 100 companies had responded to an appeal for help four weeks ago but had heard nothing since.
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