A 250 tonne piece of the Rena has been ripped off the wreck and fallen to the seabed.
Vital salvage equipment also went overboard.
Today, Maritime New Zealand said high wind and rough seas this week caused a large piece of the fore-section to be ripped free from the aft portside of the wreck.
The piece that came off the ship was about 25m long and weighed about 250 tonnes.
The section included the boat landing platform and access ladder, with gas cutting equipment also going overboard.
No salvors were onboard at the time and the loss of equipment has not delayed salvage efforts.
Francis Leckey, senior salvage master of the Florida-based salvage company Resolve Salvage & Fire, inspected the wreck.
"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.''
Meanwhile, salvors are continuing to work onboard the wreck.
In their bid to reduce the wreck to below the water-line, salvors removed approximately 45-50m pieces of steel this week.
These pieces, which weighed about 100 tonnes, were removed from the forecastle, aft portside and transverses.