The first crash, which involved three vehicles, happened at 2.40pm in Tyne St near the intersection with Harbour St when a driver failed to give way when they pulled out of a car park and their car collided with another vehicle.
Both sustained minor damage.
A third vehicle was also damaged and the street was blocked for a short time.
Staff from nearby businesses helped direct traffic until the vehicles were moved.
That was followed by a two-vehicle crash at 4.05pm in Reed St, near the intersection with Ouse and Derwent Sts, when a driver failed to give way at a stop sign and hit another vehicle.
Once again, both vehicles suffered minor damage.
The final crash, which also involved two vehicles, occurred at 5.50pm in Thames St, near the intersection with Wear St.
Sgt Tony Woodbridge described it as a "low speed crash", that caused minor damage to both vehicles.
Two fire appliances and an ambulance were called but were stood down shortly after they arrived.
None of the crashes resulted in injuries.
"This is a short period of time for three crashes. They will be a bit shaken physically and financially, because it’s a major thing to be in a crash of any kind."
He advised motorists to take care and be patient when driving, particularly during peak times and around road works.
"I would ask people to take care and know what is going on around them. There’s road works at the moment and I know a lot of people get frustrated. People need to take their time because it doesn’t take long to get places here."
A stretch of State Highway 1 in central Oamaru, between Orana Park and Exe St, was being worked on by the NZ Transport Agency and motorists should expect delays, he added.
