Svitzer Salvage says divers on the Rena will be able to give a comprehensive picture of what is going on beneath the water on Tuesday or Wednesday.
The container ship broke in two in rough weather on 7 January after going aground the Astrolabe Reef, off Tauranga, on 5 October.
Rough seas had prevented divers from getting a good look at the sunken rear section.
But Svitzer Salvage spokesperson Matthew Watson said that divers have finally been able to go to considerable depths to view the containers and debris.
He said the divers now have a far better understanding of what has taken out of the rear section of the ship and will present a report to the salvors by later on Tuesday or on Wednesday.
However, Mr Watson said the sea swells are still too big to allow the salvage operation to swing back into full gear.
Work on removing the remaining containers from the deck of the bow section will be a priority for either Tuesday or Wednesday, he said.