Residents in Wellington and the top of the South Island are being warned there's a 93 percent chance of an aftershock between magnitude 6 and 6.9 in the next month.
GeoNet has issued its latest probabilities of earthquakes and their sizes following Monday's magnitude-7.8.
Where the aftershocks are forecasted to happen (GeoNet)
It says the most likely scenario is that aftershocks will continue to decrease in frequency over the next month, but magnitude 5 or higher shakes will continue to be felt near the epicentre, along the Kaikoura coastline and the Cape Palliser/Wellington area.
GeoNet says the new probabilities are based on the uplift in the original recorded magnitude of Monday's quake from 7.5 to 7.8.
It stresses they use probabilities because "we cannot predict earthquakes".
GeoNet released a table with the chance of aftershocks for the next day, week and 30 days, but says tremors from the Kaikoura sequence are expected to continue for "months to years".
There table shows a 99 percent chance of a magnitude-5 to 5.9 aftershock both within a week and within 30 days.
Aftershocks are most likely to happen in the red box area in the map, which includes north Canterbury, across to Nelson, Marlborough, Kaikoura and Wellington.
GeoNet says while such data can be distressing to some, it can be helpful for people to have an idea of what could come.
"We understand that aftershocks can be upsetting for some people. These feelings are completely normal. Seek support with friends and family."