"People in Wellington and Gisborne also reported feeling the quake but it's highly unlikely they felt it. They probably felt a separate smaller, localised quake."
It was unlikely the quake had caused significant damage, he said.
"A few things may have fallen off shelves, but I would be surprised to hear if there was much damage because of its offshore location."
Emergency services have not received any reports of damage or injuries from the latest Christchurch quake, the second largest aftershock since Sunday.
Some people have posted messages online about the earthquake.
The city is just days away from commemorating the five-year anniversary of the deadly February 2011 quake that claimed the lives of 185 people.
Meanwhile, a light 3.7 magnitude quake has just rattled Gisborne.
The quake was centred 30km east of the city at a depth of 32km.