A 4.6-magnitude aftershock shook Christchurch tonight and a similar sized quake has rattled Wellington.

The aftershock struck 10km south of Christchurch and 10km west of Lyttelton at a depth of 5km, GeoNet reported.

There were no reports of damage, Radio New Zealand reported.

Meanwhile, a 4.5-magnitude earthquake rattled Wellington.

The quake struck at 10:07pm, and was centred 20km northwest of Wellington at a depth of 40km, GeoNet reported.

The quake was felt strongly as far north as Otaki and as far south as Blenheim.

There were no reports of damage, a Fire Service spokeswoman said.