Police investigating the deadly cluster of COVID-19 cases aboard the Ruby Princess have pinpointed a waiter or crew person handling food as the likely source.

A team of detectives has been aboard the cruise ship docked at Port Kembla since last week, probing how the vessel was allowed to dock at Sydney’s Overseas Passenger Terminal and let 2650 passengers off even though 13 were still being tested for coronavirus.

Some 600 cases in Australia and more among the 900 overseas guests led to the probe, and 200 have already come forward to help in the investigation, and the hunt for “Patient Zero”, the person who brought the disease on board.

A blame game between NSW health and Australia’s Border Control officials over who was responsible for the bungled disembarking continued yesterday over how the ship became Australia’s number 1 source of the virus.

Border Force head Michael Outram called for a “hardening” of biosecurity at Australian ports.  According to The Australian newspaper “agencies examining the conduct of the ship’s operator, Carnival Cruises, are understood to have been left astonished at the lax approach to overseeing the integrity of the nation’s seaports compared with its international airports”.

NSW Police Commissioner Mick Fuller, who is leading the State’s battle with coronavirus,  said at a press conference early indications suggested an infected crew member was most likely responsible for the outbreak on the Ruby Princess.

“That would seem to be the most obvious point of transmission — someone that is handling food on behalf of multiple hundreds of people,” he said.

The crew remain aboard the stricken vessel, which is currently expected to sail for its home port on Wednesday. However, fresh assurances were given that those found to have the virus would be treated in Australia before the ship was allowed to leave after strong representations from maritime unions.

The crew remain upbeat, and Mr Fuller revealed many did not want to leave the ship.  Sixty-six crew have so far returned positive results for the virus.

“We are making every effort to get people home and we are working with Carnival to do that,” said Mr Fuller.

“We are not going to run the ship out of port if there’s multiple sick people who require a high degree of medical assistance — we won’t do that.”

Meanwhile, legal firms are now circling after passengers complained that Princess Cruises allowed passengers to mingle after cases of sickness had appeared aboard the ship.

Two American passengers filed a negligence lawsuit against Princess Cruise Lines Thursday in the federal court in Los Angeles.

The elderly couple, David and Donna Rumrill, were aboard the Ruby Princess, which sailed out of Sydney, Australia, on March 8 and had to return three days early on March 19 as a result of an outbreak of acute respiratory infections, according to their complaint seeking at least $1 million in damages.