A 250-tonne section of the Rena has fallen to the seabed after high winds and rough seas pounded the stricken container ship this week.
The 25-metre chunk of fore section was ripped from the aft portside this week, Maritime New Zealand said today.
"This section included the boat landing platform and access ladder, with gas cutting equipment also going overboard."
No one was on board at the time.
Salvors continue to work on the ship and in the past week have removed about 45 to 50 pieces of steel.
Rena ran aground on Astrolabe Reef off the Bay of Plenty coast as it headed for Tauranga early on October 5, spewing oil and debris across the area.