A Sandringham dairy owner says one of his regular customers was stabbed by a group of teenagers who robbed his business.

Selvathas Ariyathas owns the Sandringham Foodmarket which was robbed around 11pm last night.

He was in the shop, serving two regulars, when four people came into the store demanding money and cigarettes and threatening him.

Ariyathas says they looked to be around 16 or 17, but had their faces fully covered.

The group took the contents of one till, around $1000 and around $7000 worth of cigarettes and then headed to the street as one of Ariyathas' regulars attempted to stop them.

The man was then allegedly stabbed by the youths.

"This person he fought them, and then after they stabbed him, they ran away."

Police talk to a person outside Sandringham Foodmarket. Photo / Hayden Woodward

Ariyathas says he is grateful to the man for his bravery.

The situation was frightening, and he told the Herald he will now reduce the hours his shop is open out of safety concerns.

"It's a very bad situation, it's not safe for us. We have to reduce our hours, and because of this, our sales will go down."

Detective Senior Sergeant Steve Salton told the Herald inquiries are under way to find the alleged offenders after they fled the scene in a vehicle.

"Unfortunately, a member of the public sustained minor injuries after attempting to intervene when he saw the incident unfolding.

"These were not life-threatening injuries and the man received medical treatment at the scene, but was not transported to hospital."

Anyone with further information is asked to contact the police on 105 and quote file number 220602/7468.