A 16-year-old boy was targeted with the substance inside the Coles store about 2.30pm on Thursday.

The spray was sucked into a nearby air conditioning vent, causing it to quickly spread throughout the Clyde Street premises.

Sergeant Paul Evans said police had been keen to speak to two people of interest.

“It’s a community environment,” he said.

“It’s reckless behaviour and it’s impacted on a number of people young and old.

“These people could have had pre-existing medical issues.

“It could have potentially resulted in quite serious medical episodes.”

Sergeant Evans said at least eight people had been affected by the spray and three people were still receiving medical treatment from their doctors. 

It's illegal to own the spray, which is similar to the type used by police, in Victoria. 

He said the spray could also be physically transferred between people.

“The police have intentions to speak to two males that were suspected of releasing the pepper spray type irritant,”he said.

“Hopefully we will have a resolution on the matter sooner rather than later.

“We’ve got to speak to both those people to work out their roles in the incident.”

Police have retrieved security camera footage of the offence, which occurred in one of the aisles. 

“There are also some eye witness accounts,” Sergeant Evans said. 

“We're seeking any other witnesses who haven't made a statement to come forward and contact me at the Myrtleford police station.

“It's just not acceptable behaviour. 

“Paramedics attended the scene and had to treat people.

"That's the way these spread unfortunately – they get propelled into the air. 

"The air conditioner uses recycled air and would have dispersed it throughout the store.”

Police are also investigating where the spray was sourced.

The 16-year-old victim knew the alleged attacker, but police have not said how. Anyone with information should call (03) 5752 1003.