The quake struck at a depth of 30 kilometres simply after 4pm native time right now and was felt from Kaitaia to Dunedin, with folks close to the epicentre feeling a large jolt.
Its epicentre is believed to be about 30km south-west of Seddon, in South Marlborough.
Seddon residents Terry and Karen Renner mentioned they heard the earthquake earlier than they felt it.
"We did get a little bit of a fright. We have been outdoors, standing out the again and we heard a large bang," Ms Renner mentioned.
"We have a giant shed up the again and that is what actually shook.
"We seemed on the truck and it was rocking and rolling."
However nothing had been damaged, she mentioned.
She was ready for aftershocks however hadn't seen any.
"The TV remains to be standing, so all the things's OK."
The Renners have lived via plenty of main quakes, with Seddon being on a fault line that ran up the Awatere Valley.
That included the 2013 Seddon earthquake and the 2016 Kaikōura earthquake, each inflicting injury to the home that wanted repairs.
"Nicely we thought it could not have been too huge. Usually if there is a huge one folks all come outdoors their homes, collect on the road, within the township. All of us be certain our neighbours are OK."
Mr Renner was off to test for injury on the rugby clubrooms.