Sharks have attacked sonar equipment used to find containers that have fallen off the cargo vessel Rena.
Maritime New Zealand says the sonar equipment could not be used on Sunday because of the shark attack.
The vessel has been stuck on the Astrolabe reef off the coast of Tauranga since 5 October.
Seventeen more containers were recovered from the vessel over the weekend while another, carrying meat products, fell overboard and was later recovered.
A total of 89 containers have fallen overboard and more than 50 are unaccounted for.
In all, 227 containers have been recovered from the wreck. More than 1000 are still to be removed.
Maritime New Zealand says buckling on the ship's starboard side is continuing to develop and is being monitored.