WELLINGTON: A strong 6.1-magnitude earthquake rattled New Zealand on Wednesday, striking the same area hit by a massive tremor last month that was the country's biggest in nearly 80 years.

The epicentre of the undersea quake was located about 187 kilometres (116 miles) west-northwest of the city of Invercargill, on South Island, at a depth of 10 kilometres, the US Geological Survey reported. It struck at 0831 GMT.

A 7.8-magnitude quake rocked the same area on July 15, prompting a brief tsunami warning but no casualties or major damage.

That was New Zealand's biggest earthquake since 1931, when a 7.8 tremor killed at least 256 people in the North Island city of Napier.

Earthquakes are frequent in New Zealand, where the boundaries of continental plates meet as part of the Pacific "Ring of Fire," causing earthquakes and volcanic activity.LINK