The government said alternatives to fluid-repellent full length gowns may need to be used. Britain is near the peak of an outbreak of the coronavirus in which more than 14,000 people have already died.
Doctors and health workers criticised the British government on Saturday for suggesting that gowns used to protect them while treating coronavirus patients could be reused, as supplies run low across the country.
On Friday the government issued new guidance to hospitals, setting out that alternatives to fluid-repellent full length gowns may need to be used, including reusable gowns or even long sleeved laboratory coats.
"This guidance is a further admission of the dire situation that some doctors and healthcare workers continue to find themselves in because of government failings," said Rob Harwood, Consultants Committee chairman at the British Medical Association, the trade union for doctors.
"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."
Britain's response to the coronavirus outbreak, which has lagged that of European peers, is a source of increasing political criticism for Prime Minister Boris Johnson, who himself contracted the virus and is now recovering from a spell in intensive care.
Health minister Matt Hancock told a committee of lawmakers on Friday that Britain was "tight on gowns" but had 55,000 more arriving and was aiming to get the right equipment where it was needed by the end of this weekend.
A health department spokesman said the new guidance was to ensure that staff knew what to do to minimise risk if shortages did occur. They said the new rules remained in line with international standards.
The Royal College of Nursing said it had written "in the strongest terms" to express their concerns over the rules change, and said they had not been consulted about them.
NHS Providers, a body which represents hospitals and other parts of Britain's publicly funded National Health Service (NHS), said supply levels of gowns were critical.
"It is now clear that some trusts will run out of fully fluid repellent gowns this weekend," deputy chief executive Saffron Cordery said.
The body said China was the only immediately available source of the gowns, meaning there was international competition for supplies. It also said there had been problems with consignments arriving from China, such as stock labelled as gowns actually containing face masks.