Two earthquakes shook parts of the South Island on Saturday night, one near Christchurch and the other at the top of the island.

The first struck at 10.30PM within five kilometres of Christchurch. GeoNet reported it was a light magnitude 3.1 quake at a depth of nine kilometres.

Despite its small size, the shallow depth meant it was widely felt.

More than 3400 people lodged reports with GeoNet.

An hour later, at 11.31PM, a stronger quake was recorded 10 kilometres south of French Pass.

The magnitude 4.8 tremor was at a depth of 55 kilometres and produced moderate shaking.

More than 6300 people reported feeling it.