Fresh images have emerged of a capsized Banks Peninsula tour boat as authorities prepare to deliberately sink the vessel in a bid to limit the environmental impact.

The Black Cat Cruises vessel, which was carrying more than 2000 litres of marine diesel fuel, remains partially submerged today after it capsized on Saturday during a dolphin sightseeing tour near Akaroa, Canterbury.

Coastguard Akaroa volunteers said they overheard a ‘pan-pan’ call for assistance and arrived at the scene to find several other vessels already helping those on board.

All 38 passengers and three crew members on board were evacuated.

The latest photos of the sunken vessel. Photo / Supplied

Environment Canterbury Regional On Scene Commander Emma Parr today said recovery efforts are now focused on stabilising the vessel to prevent further damage and monitoring the impacts from the spill.

“This involves moving the vessel into deeper water, where it can be submerged in a controlled manner to prevent further structural damage from wind and sea conditions,” Parr said.

She said environmental monitoring was ongoing, and wildlife response specialists remained on standby throughout the operation.

The latest photos of the sunken vessel. Photo / Supplied

Environment Canterbury confirmed all diesel fuel on board the vessel is believed to have been released into the sea.

“It is likely that the full amount of marine diesel fuel that was on the vessel has been released to the sea,” the regional council said in a statement yesterday.

“Observations are showing us that the environment is coping with the release of this fuel, with sheens decreasing throughout the day.”

Environment Canterbury said wildlife specialists and precautionary measures were also in place to mitigate any environmental impacts.

A Black Cat cruise boat capsized near Akaroa. Photo / Supplied

The Transport Accident Investigation Commission (TAIC) has appointed a dedicated investigation team to examine the incident.

Chief investigator of accidents Louise Cook said the agency was seeking information from anyone who was on board or witnessed the event.

“We’re particularly keen to receive videos or photographs,” Cook said.

The Herald approached Black Cat Cruises for comment, but the company said it was not speaking to media at this stage.