An earthquake measuring 5.9 magnitude centred in Fiordland was felt widely in the lower South Island tonight, following two other quakes earlier in the evening.
The latest tremor at 8.31pm was centred 120km west of Te Anau.
While GNS Science measured it at 5.9, the US Geological Survey registered it at 6.1. Geologists say the measurements of quakes are often more accurate from a long distance because of how shock waves travel through the earth.
Invercargill police said there were no immediate reports of any damage.
"The phones are quiet," a police spokesman said.
There were two earlier quakes - one measuring 5.2, 100km west of Te Anau, at 4.25pm and the next at 4.8, at 7.07pm. It was centred in Fiordland, 110km west of Tuatapere.
GNS Science said the quakes were all aftershocks from the 7.8 magnitude Fiordland quake that struck on July 15.
The 5.9 quake was one of the largest aftershocks recorded since that, duty seismologist Lara Bland said.
More than 200 people had logged reports on tonight's latest quake on the GNS website, she said.
