Thousands of people have been jolted awake by an early morning quake in Wellington.

The magnitude 4.9 tremor hit at 6.34am on Saturday, centred about 30km north-west of Paraparaumu, at a depth of 26km.

GeoNet has described the shaking as moderate.

More than 21,000 people reported feeling the quake immediately afterward, with reports concentrated from the Marlborough and Nelson areas in the South Island, up to the Central Plateau - and the strongest reports from the Kāpiti Coast, Wellington, Wairarapa, and top of the South Island.

An RNZ reporter in Lower Hutt said the furniture began shaking against the wall in her house, and neighbourhood dogs soon started barking, with the shaking going for some time.

GeoNet posted that their team also felt it: "The earthquake was felt in our National Geohazards Monitoring Centre in Lower Hutt, who heard the quake coming and report it had definite primary and secondary wave arrivals, which makes the quake feel longer."

A Raumati South man said: "I was asleep, but woken by a noise you could hear coming... like a close freight train.

"Then a decent shake for about 10 seconds and a wobble. During the wobble, my phone alert went off, despite my phone being on silent. No damage, and I have felt stronger quakes here..."