A contractor for the London Ambulance Service has been arrested on suspicion of stealing "a large number" of face masks.
The man, in his 20s, was arrested at the Edmonton Ambulance Station on Wednesday morning.
The Met Police alleged the man was trying to sell the face masks and other products online.
He has been bailed until a date in mid-April, the Met Police added.
Det Insp Jason Colby said he was "saddened" anyone would "take advantage of the NHS for their financial gain".
"These masks are a vital piece of PPE for emergency service personnel and are used to keep both themselves and patients safe," Det Insp Colby added.
"We will continue to crack down on anyone attempting to take advantage of our emergency services for personal gain, especially at such an unprecedented time."
Officers were able to recover a number of items during their searches and these have been returned to LAS.