Face coverings have become the fastest-selling items in Co-op stores, outselling essentials such as milk.
The retail giant said there has been a surge in demand as a result of the coronavirus crisis.
The Co-op started selling non-medical graded face coverings at the end of May in its 2,600 stores.
Joseph Turner, Co-op buying manager, said: “We know it’s important to reserve valuable PPE for health and care workers, so these are not suitable for medical use but have been designed with customers in mind and are just one way we can be careful, along with social distancing and washing our hands.
“Following the demand, we have secured more stock to ensure we can continue to serve the nation.”