Banking giant HSBC has issued a warning to any of its customers refusing to wear a mask without being exempt.
People who refuse to wear masks inside its banks risk having their accounts withdrawn.
The lender - which also owns First Direct and Marks & Spencer bank - said customers who break the law could forfeit their bank account.
Speaking to The Mirror, a spokesman said face masks are mandatory in all branches as per government guidelines.
Those who refuse to comply will be refused service and could have their bank accounts withdrawn.
Jackie Uhi, head of branch network, HSBC UK said: "Our branch colleagues are key workers, continuing to go to work in our branches every day so that customers who need them can access essential financial services.
"Sadly, some people are failing to protect themselves, our branch colleagues and other customers by refusing to wear a face covering inside our branches or observe social distancing.
"Our colleagues deserve respect and should not have to face violent or abusive behaviour. Consider whether you need to visit the branch or could manage your banking from the safety of your home via our digital channels.
"If you do visit us, please wear a face covering and maintain a safe distance from others. If individuals put themselves or our colleagues at risk, without a medical exemption, we reserve the right to withdraw their account"
The Mirror has also asked Santander, Barclays, Lloyds, Natwest and Nationwide for updated guidance and will update this story in due course.
The Post Office said customers must obey the law, but warned it will not be enforcing measures
"Postmasters that they can ask a customer who is not wearing a facemask if they are medically exempt, but the customer is not required to provide medical proof if they do not have it with them when they visit a branch," a spokesman said.
"Post Office will implement any updated guidance issued by the UK Government or Devolved Governments. At this stage, Post Office has not advised Postmasters to refuse entry to any customer that does not have a face mask.
