Inspector Craig McKay said that, at this stage, the intention is to deploy the Navy's remote operated vehicle (ROV) to confirm the identity and orientation of what police say is an "item of interest" located in 40m of water near to the last known position of the FV Jubilee.
A massive search has been underway since it went down.
On Sunday, searchers found a liferaft, but no sign of the fishermen.
The families of the missing crew are being supported by police, Victim Support, the crew's Lyttelton-based employer and their respective friends and family, Mr McKay said.
"It's a difficult time for both the company, and obviously, more so for the families," said Andrew Stark, chief executive of Ocean Fisheries and Stark Bros said on Sunday.
The three men on board were familiar with the Jubilee, Mr Stark said.
"They're all experienced with the boat," he said.
A police investigation into the sinking is ongoing, while the Transport Accident Investigation Commission (TAIC) has also opened an inquiry.
A team of two TAIC investigators have begun gathering information and working with search authorities and the fishing company on an investigation plan.
The plan includes options for inspecting the sunken vessel.
The commission said the aim was to find out what happened and why, in order to prevent a similar situation happening again.
Yesterday, a police dive squad involved in the effort to retrieve the vessel and its missing crew were forced to turn back because of a mechanical issue on their own boat.
