The quake was strong enough to prompt some stores to evacuate customers and shake items from shelves. Police said there were some rockfalls on Scarborough Hill in the city's east and were advising people to stay away from affected areas.
The St. John ambulance service reported that several people had suffered minor injuries from falls as they ran from the quake.
The earthquake came close to the anniversary of the Feb. 22, 2011, magnitude-6.3 temblor that leveled much of the center of New Zealand's second largest city and killed 185 people.
The U.S. Geological Survey reported that Sunday's quake was centered 17 kilometers (11 miles) east of the city at a relatively shallow depth of 8 kilometers (5 miles). Shallow earthquakes tend to be felt more strongly. No tsunami warning was issued.
The quake was one of the largest since 2011, and people from across the South Island reported feeling the ground shaking.
New Zealand sits on the "Ring of Fire," an arc of seismic faults around the Pacific Ocean where earthquakes are common.
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