Amid fears over NHS staff shortages, the head of the Doctors' Association UK said existing staff may feel forced to leave because they do not have adequate personal protective equipment (PPE) to safely treat Covid-19 patients.
The letter from the RCN added that nurses require testing so that staff with possible symptoms know whether they are infected or not. "And that is what our staff are crying out for - they want the right equipment so we can do that".
After a doctors" leader said earlier this week they felt they were being treated like "lambs to the slaughter", Mr Hancock admitted there have been "challenges'.
"What our doctors are telling us is that although equipment is arriving, some of it is inadequate, some of it doesn't meet the World Health Organisation guidance".More news: NYC schools unlikely to reopen this year, de Blasio says
In a letter pleading with Prime Minister Boris Johnson to increase PPE supplies, over 6,000 frontline doctors said they were being asked to put their lives at risk with out-of-date masks, and low stocks of equipment.
It comes amid reports that a number of medics are seriously ill after becoming infected with Covid-19, including a nurse with no underlying health issues.
Millions of gadgets have been offered to hospitals, ambulance trust, GP practices, care properties and other well-being services in the last few days, he added, after complaints emerged from medical staff that they didn't have enough package.
During the daily Downing Street briefing on coronavirus, Mr Hancock said: "Many, many people across the NHS are asking for more personal protective equipment (PPE)".More news: Panthers signing former Jets WR Robby Anderson
"There have been challenges and I can see that".
The Welsh Government said it was distributing supplies to the NHS, with plans being made for social care too. This is incredibly important to protect our NHS staff and social care staff who need the masks as well.
The area has been overwhelmed with visitors", he said.The government warned that Britain would face a shutdown with curfews and travel restrictions if people continued to flout the advice."Well, we're perfectly prepared to do that if we need to because the objective here is really clear which is to stop the spread of the virus.
"We are working round the clock to make sure trucks are on the ground across the country delivering protective equipment to all who need it, so they are well-equipped to continue to fight the virus".More news: WH Urges People Who Left NY Recently To Self-Quarantine
Emily Lawson, chief commercial officer for the NHS, said: "We need massively increased, urgent volume of these supplies to the frontline in this exceptional set of circumstances. We are extremely grateful for the army's support in doing so".