The quakes forced people to flee in panic from buildings. There were no initial reports of injuries.
Christchurch has been shaken by thousands of aftershocks since a 6.3-magnitude quake killed 181 people in February.
A series of tremors were felt on Monday, the largest of which the U.S. Geological Survey recorded at magnitude 6.0.
One of the temblors trapped two people inside St. John's Church, which mostly collapsed in the February quake. Police said they have since been rescued. Another building nearby was brought down, but no one was inside.
People attending inquest hearings for victims of the Feb. 22 earthquake reportedly bolted from the Riccarton Park Function Center when Monday's quakes struck. Others fled from buildings at Canterbury University and the Westfield Riccarton Mall, which also suffered heavy damage in February.