Police have released CCTV images of two people they are looking for in relation to the death of a mystery diver found near a $20 million cocaine haul at a NSW port.

Detective Superintendent Robert Critchlow said on Friday the pair were likely in the Newcastle region between May 1 and 11.

One is a man described as South American in appearance, 178 centimetres tall and of an athletic build.

The other is a woman, who is described as thin, tanned, about 150-160 centimetres tall and with blonde or grey hair.

Detective Supereintendent Crtichlow said the man could be dangerous roaming in the community and said they both entered the country illegally via ship.

He also estimated that another 50 kilograms of cocaine had hit the streets already.

Police on Tuesday revealed the dead diver – identified as a foreign national – was found unconscious in the water at the Port of Newcastle and was unable to be revived.

The dead man was found near 54 kilograms of cocaine and it is believed he was diving to retrieve them.

The diver had sophisticated equipment, including a “rebreather” apparatus that allows the user to breathe underwater without any telltale bubbles rising to the surface.

“This really is a high level, very organised, highly sophisticated operation directly bringing large amounts of dangerous drugs … across the oceans into Australia,” Detective Superintendent Critchlow said.

He also alluded to the transnational dimensions of the illicit shipment extending to neighbouring Indonesia.

Indonesian authorities on Sunday said four packages of cocaine weighing 180 kilograms, with a street value of more than $80 million, were discovered near Java’s Merak Port after being dumped in the ocean.

“The logistics of this operation were huge with many moving parts and we’re also looking at Indonesia and what may have happened there,” Detective Superintendent Critchlow said.

Earlier this week police in north Queensland arrested a 62-year-old foreign national, James Blee, believed to be linked to the drug find, after he allegedly tried to flee the country.

He will be extradited to NSW on Friday from Cairns.

Police have also docked a Marshall Islands-registered cargo ship, which was nearby at the time, after it arrived from Argentina on Sunday.

Authorities have searched the ship, investigating theories the drugs may have been thrown from the ship or attached to its hull, and the diver may have drowned while trying to retrieve them.

The investigation involves police from NSW, Queensland and the Northern Territory, as well as Australian Federal Police and Australian Border Force officials.

– AAP