The pair of strong quakes which hit Te Aroha in the last week are the first in nearly 51 years, according to Geonet.

In a post to Twitter, the geological monitoring service says the magnitude 5.1 quake which hit at 5.39am this morning is "in the same spot" as the magnitude 3.9 earthquake recorded last week in Te Aroha.

"The quakes are likely on the same fault system, the area last having a strong quake in 1972 with the magnitude 4.9 Te Aroha earthquake," the post says.

A 1972 bulletin, published by the New Zealand Society for Earthquake Engineering, reports a 5.1 magnitude quake in the area, with damage confined to the region but also felt as far as Mangakino and Whakatāne.

There was also says to be numerous aftershocks the next month.

Geonet also adds the earthquake is a good "reminder" that earthquakes "can occur anywhere in New Zealand at any time."

"In the event of a large earthquake: Drop Cover and Hold."

The quakes are likely on the same fault system, the area last having a strong quake in 1972 with the M4.9 Te Aroha earthquake, and a reminder that earthquakes can occur anywhere in New Zealand at any time. In the event of a large earthquake: Drop, Cover and Hold. pic.twitter.com/vnuJgo5k9C

— GeoNet (@geonet) January 3, 2023

The 5.1 magnitude quake hit at a depth of 7km about 5km south of Te Aroha in the Waikato region at 5.39am.

More than 20,000 people reported feeling a shake in the areas nearby, including Hamilton, Tauranga, Auckland, and Rotorua.

The aftermath of the quake from a resident living 10km from Te Aroha. Photo: Supplied/RNZ.

It was followed by two 2.7 magnitude earthquakes in the same spot at 5.47am and 5.51am.

About 8000 people reported feeling the first aftershock, and about 4000 reported feeling the second.

Truck driver Darryn Phayer says his 25-tonne truck swayed sharply in the first earthquake.

"The truck started violently shaking and I thought 'oh what's going on here', but literally, prior to that, in the farm across the road from the yard, a bunch of dogs started barking and I thought 'oh what's upset them' and within a couple of minutes, it was up on GeoNet.

"[It] scared the living daylights out of me, to be honest."

On the east coast, Pauanui resident Christine Harrison says it was the strongest quake she had ever felt.

"It was a strong jolt in that it made me grab the edge of the bed to really hold on but as quickly as it started, it stopped."

Later in the morning, 2.6 and 2.7 magnitude quakes hit south of Te Aroha again, just before 8am.

- Additional reporting by RNZ.