A 250 tonne piece of the Rena has broken off and fallen to the seabed.
High wind and rough seas early this week resulted in about 25m of the fore section ripping free from the aft portside, Maritime New Zealand said today.
The section included the boat landing platform and access ladder, with gas cutting equipment also going overboard.
No salvors were on board at the time and the loss of equipment had not delayed salvage efforts.
Francis Leckey, senior salvage master for US firm Resolve Salvage and Fire, inspected the wreck when the weather cleared.
"While on board, the wreck was still rolling and pitching,'' he said. ''From the visual inspection there was a slight increase in the trim of approximately 2-3 degree heel to starboard."
Salvors continue to work on board.The news came after the Rena captain and navigation officer were deported back to the Philippines yesterday.
Ship captain Mauro Balomaga, 44, and navigator Leonil Relon, 37, were released from prison on Wednesday, after serving half of their seven-month sentence.
They had pleaded guilty to operating a vessel in a manner likely to cause danger, discharging a contaminant and altering ship documents.
Balomaga's lawyer Paul Mabey QC yesterday confirmed his client and Relon would have jobs to go to.
He did not know whether Balomaga would be going back to sea.
Meanwhile, Resolve continued to work on reducing the size of the wreck. It had removed about 45-50 pieces of steel which weighed 100 tonnes. These pieces were removed from the forecastle, aft portside and transverses.
Work was also continuing today on debris recovery, using the newly arrived Tasman Challenger, a 30m vessel fitted with a crane.
The Braemar Howells/Unimar team spent time this week putting down moorings for operations that will occur on the seabed around the Rena.
The vessel is to be hooked on to those moorings this afternoon and baskets will be dropped down and loaded with debris by divers.