A police spokesperson said officers were called to reports of a robbery at the Opawa Rd dairy about 6.40am.
The offenders fled the scene in a vehicle and police cordoned off the area.
Hato Hone St John took one person to hospital with moderate injuries.
Police said the search for three offenders, whose faces were covered during the burglary, was continuing.
It follows a spate of youth crime in Christchurch.
In May, 162 young offenders were dealt with by police in the city. The number of youth offenders has remained high since, with police dealing with about 100 a month.
Canterbury Police District Commander Superintendent Tony Hill said on Sunday two boys were arrested in connection with a string of aggravated robberies, one of which saw a dairy worker attacked with a spanner.
Two other businesses - on Blighs Rd in Strowan and on Clyde Rd in Riccarton - were also targeted on Sunday.
Todd said the two 13-year-old boys were facing three counts of aggravated robbery.
Allied Media & RNZ
