NHS trusts were not consulted on plans for all hospital staff to wear surgical face masks and visitors and outpatients to wear face coverings from June 15, a healthcare chief has claimed.
The Government has been accused of making the decision "on the hoof" that one healthcare chief said seemed "overly influenced by politics".
Health Secretary Matt Hancock announced the new policy on face coverings in hospitals at Friday evening's Downing Street coronavirus press conference.
But NHS Providers deputy chief executive Saffron Cordery says NHS Trusts received "little or no consultation" ahead of the Government's announcement on imminent changes to face covering regulations.
She said it has left NHS Trusts scrambling to find enough equipment to cater for hospital staff, patients and visitors.
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The Department of Health claimed that NHS England was fully aware of the announcement before it was made public and said that trusts have all of next week to implement the changes.
Ms Cordery said: "The announcement of compulsory mask wearing for all NHS staff working in any part of a hospital is clearly designed to help to ensure that both staff and patients are protected and feel safe.
"But, as is the case for a number of announcements throughout the pandemic, this has come with little or no consultation with the NHS frontline and without a plan in place to ensure that all trusts will have access to adequate supplies of type one and two masks."
Ms Cordery also added trusts were nervous about the imminent lifting of some patient visiting restrictions from June 15.
"We know that trusts want to do all they can to ensure that patients can have contact with their loved ones while in hospital, but there is understandably nervousness and concern about opening up visiting too quickly," she said.
"Trusts need time to put in place processes and guidance to ensure that patients can receive visitors safely and while adhering to social distancing and infection control measures.
"Important decisions like these should not come as a surprise to those expected to deliver them."
A Department of Health and Social Care spokeswoman added that, while members of the public are "strongly urged" to attend hospital wearing a face covering, no one will be denied care and masks will be provided by the hospital if necessary.
And Mr Hancock said the Government wanted to ensure that "even as the virus comes under control", hospitals are a place of "care and of safety".
Chris Hopson, chief executive of NHS Providers, also slammed the new announcement backing Ms Cordery's claim that Trusts had received no notice or consultation.
Mr Hopson told BBC Radio 4's Today programme: "Two major changes on the use of personal protection equipment and on visiting policy were announced late yesterday afternoon at the end of what, to be frank, was a very busy, difficult and hard week for our trust leaders, with absolutely no notice or consultation.
"I think it's the latest in a long line of announcements that have had a major impact on the way the NHS operates in which those frontline organisations feel they have been left completely in the dark and they are then expected to make significant and complex operational changes either immediately or with very little notice."
He said political leaders "need to understand that running these organisations is a complex and difficult task and what you can't do is turn on a sixpence" with major policy announcements.
Ms Cordery's and Mr Hopson's criticism was echoed by the British Medical Association, which warned there was "little detail" on how the policy would be implemented, where the masks would come from or how outpatients and visitors would be given them.
Consultants committee chair Dr Rob Harwood said: "Given the lack of PPE supplies throughout the Covid-19 pandemic, it is absolutely crucial that the Government ensures there are enough supplies of face masks for staff, and adequate provision of face coverings for outpatients and the public by the 15th June."
It comes amid fears over the coronavirus reproduction rate in parts of England as new data suggested the R value is now around one in the North West.
The value used by the Government remained between 0.7 and 0.9 for the UK as a whole, though the figure has a two to three-week lag, meaning it does not account for the latest easing of the lockdown.
Deaths in UK hospitals so far: 31,469
Deaths across all settings: 40,261
(The two figures above count all people who have had a positive test result confirmed by a Public Health or NHS lab in the UK)
Total deaths registered so far: 43,837
(This is the number of registered deaths in England and Wales where Covid-19 was mentioned on the death certificate)
Excess deaths so far in 2020: 56,308
(The number of deaths in England and Wales above the average amount, but not necessarily caused by Covid-19)
Sources: coronavirus.data.gov.uk and ONS
But a separate report from Public Health England (PHE) and Cambridge University, which estimates what the value is currently, put the North West on 1.01 and the South West on 1.00.
Mr Hancock said that new figures on the R confirm "there is a challenge in the North West of England to address and, to a lesser degree, in the South West of England".
He said the Scientific Advisory Group on Emergencies (Sage) believes the R is below one across the UK but the Government wants to "increasingly have an approach in tackling local lockdowns where we spot a flare-up".