The latest aftershock follows this morning’s strong 5.1 magnitude shallow quake that struck south of Te Aroha at 5.39am, waking thousands across the upper North Island.
There have been seven aftershocks of 2.6 magnitude or greater since the initial jolt.
All have been regarded as weak except for the jolt that struck at 11.21am.
Geonet said this morning’s strong quake was in the same spot as a magnitude 3.9 quake last week.
It said the quakes were likely on the same fault system, the area last having a strong quake in 1972 with the 4.9 Te Aroha earthquake.
The epicentre was on the active Kerepehi fault line which runs north into the Firth of Thames.
More than 20,000 people reported feeling the quake from north of Taupo to Warkworth.
Those woken by the early morning quake said it started with a jolt followed by a few smaller jolts.
Tauranga resident Gary told Newstalk ZB said it carried on rolling for about 20 seconds.
Colleen Firth also felt the quake in Katikati.
“I was asleep, and I woke up to the whole house shaking.”
She says it was noisy, and lasted for about a minute.
A Pāpāmoa resident said she felt the quake at 5.49am and the whole house shook.
Other people took to social media and Shelley Wood said “yes felt bed shaking!” while Marama Mateparae said “yes - woke me up”.
Northern fire communications said it had not received any reports of significant damage or calls for assistance following the strong quake.
