GNS Science says while the number of aftershocks in central New Zealand are decreasing, there is still a possibility for a greater than magnitude 6 earthquake.
There have been more than 1900 aftershocks of above magnitude 2 since the 6.5 earthquake on 21 July.
GNS science duty seismologist Caroline Holden says the biggest quake this week has been a magnitude 4 and in the last 24 hours there have been two above magnitude 3.
But Dr Holden says large aftershocks can still be expected with up to a 6% chance of a greater than magnitude 6 and a 47% chance of a magnitude 5 or greater in the next week.
