"When it was stopped by a police officer the driver is reported to have got out of the vehicle, discharged a firearm towards the police officer and driven off.
"The vehicle was followed at a distance by police and both occupants were apprehended by Canterbury Police AOS and an AOS dog and handler without further incident." Mr Gaskin said.
No members of the public or police were injured during the robberies or the subsequent arrests, he said.
"We would like to thank the members of the public for their patience while we worked to locate and arrest offenders."
The two people, a man and a woman, were arrested shortly before 8.30pm and both are due to appear in Timaru District Court today.
A 26-year-old Timaru man has been charged with two counts of aggravated robbery, using a firearm against a law enforcement officer, resisting arrest, two counts of assaulting a police officer, assault on a civilian and drink driving.
A 22-year-old Timaru woman has been charged with two counts of aggravated robbery.
Police said their investigations were continuing.
"Canterbury Police will not tolerate this kind of behaviour and encourage anyone who sees anything suspicious in their neighbourhood to report it to police straight away," Mr Gaskin said.