Rough weather in Bay of Plenty last week resulted in a section of the Rena's bow ripping offand falling into the sea.
The container ship ran aground on Astrolabe Reef, of the coast of Tauranga, on 5 October last year.
Some equipment being used to dismantle the bow, which remains wedged atop the reef, also fell into the sea along with the section that had broken off.
The American salvage company that is reducing the bow, Resolve, says salvage efforts have not been delayed.
The 25-metre section which broke away from the bow is now on the sea bed.