Concerns have been raised that updated government guidance on personal protective equipment (PPE) could put hospital staff and patients at risk.
Healthcare workers have been advised to reuse gowns or wear different kit, such as plastic aprons with coveralls, if stocks in England run low.
Unions representing doctors and nurses have expressed concerns about the updated Public Health England guidance.
The government said it is working to provide the PPE stocks hospitals need.
There have been warnings some hospitals could run out of the gowns used in intensive care units this weekend.
Healthcare staff treating patients with Covid-19 have previously been advised to wear long-sleeved disposable fluid-repellent gowns.
But Public Health England changed its guidance on Friday, outlining three options if the gowns are not available as "some compromise is needed to optimise the supply of PPE in times of extreme shortages".
One option is for hospitals to reserve the gowns for surgical operations and procedures which are likely to transmit respiratory pathogens.
Another is for staff to reuse "(washable) surgical gowns or coveralls or similar suitable clothing (for example, long-sleeved laboratory coat, long-sleeved patient gown or industrial coverall) with a disposable plastic apron for AGPs (aerosol-generating procedures) and high-risk settings with forearm washing once gown or coverall is removed".
Chris Hopson, chairman of NHS Providers, which represents healthcare trusts across England said some trusts will run out over the weekend.
Mr Hopson said in a tweet: "We have now reached the point where the national stock of fully fluid-repellent gowns and long-sleeved laboratory coats will be exhausted in the next 24 to 48 hours."
He said that national leaders have left "no stone unturned" – but the gowns are made in China and those that were ordered weeks ago are currently only arriving in "fits and starts".
'Lives on the line'
The Royal College of Nursing said the guidance was developed without a full consultation and the British Medical Association (BMA) – which represents doctors – said any change must be driven by science, not availability.
Dr Rob Harwood, consultants committee chairman at the British Medical Association, said: "If it's being proposed that staff reuse equipment, this must be demonstrably driven by science and the best evidence – rather than availability – and it absolutely cannot compromise the protection of healthcare workers.
"Too many healthcare workers have already died. More doctors and their colleagues cannot be expected to put their own lives on the line in a bid to save others, and this new advice means they could be doing just that. It's not a decision they should have to make."
A Department of Health spokesman said: "New clinical advice has been issued today to make sure that if there are shortages in one area, front-line staff know what PPE to wear instead to minimise risk."
The spokesman added the advice is in line with World Health Organization and Centers for Disease Control guidance on PPE use in "exceptional circumstances".
Niall Dickson, chief executive of the NHS Confederation, representing health service trusts, said the situation was "worrying" and "less than satisfactory".
He told BBC Radio 4's Today programme: "The reality is that there is a chance, and I don't think it's definite, but there is a chance that hospitals could run out or, indeed other parts of the system could run out of the gowns which are required to treat some, not all, Covid patients."
The UK announced 847 new coronavirus-related deaths in hospitals in its latest figures on Friday, taking the total to 14,576.
Elsewhere, Buckingham Palace has confirmed that the Queen will not be marking her 94th birthday next Tuesday with the traditional gun salutes this year.
In other developments:
- The World Health Organization questioned whether antibody tests will offer any guarantee of immunity against coronavirus
- Testing will be rolled out to people working in public services such as police, fire and prison staff, the health secretary has said
- Scientists at the University of Oxford said they should have at least a million doses of a coronavirus vaccine by SepRead More – Source