A man shopping without a mask at a Las Vegas Sprouts grocery store caused a scene after being told to 'wear a mask or leave' by management.

The clip, filmed on July 11 shows the man shouting at the store clerk that he has 'a constitutional right to not wear a mask' and that he had a medical condition that prevented him to.

The man in the store then erupted into anger and proceeded to shout at the manager while following him around the shop, before a fellow shopper, who happened to be a medical professional, explained that the least he could do was wear a face shield.

"It's a very timely and unique incident since the fellow shopper who confronted him was a respiratory therapist," the filmer, who wishes to remain anonymous, told Newsflare.