The criminal investigation into the Ruby Princess cruise ship debacle is expected to take another five months as authorities probe Australia’s number one COVID-19 killer.

NSW Premier Gladys Berejiklian told reporters on Tuesday the police investigation would take at least six months, with a month already passed.

Police are working with federal authorities to collect evidence from the ship and are looking into hundreds of calls made to CrimeStoppers.

NSW Health said 128 crew members on board the docked vessel had tested positive to the coronavirus with 69 of them symptomatic while 59 were no longer showing symptoms.

The Ruby Princess, which departed Sydney on March 8 for New Zealand and returned on March 19, is responsible for hundreds of COVID-19 cases nationwide including 369 in NSW and at least 18 deaths across the country.

NSW Police raided the Ruby Princess on April 9. Photo: NSW Police

Some 2700 passengers were permitted to disembark in Sydney without adequate health checks, an action blamed by the Australian Border Force on NSW health authorities.

When asked about a parliamentary commission of inquiry into the Ruby Princess, Ms Berejiklian said it was important not to compromise the criminal and coronial inquiries already underway.

“Whilst the police investigation is focusing on potential criminal activity, it will be reporting on a whole range of issues so everything from go to whoa is included,” she said.

“I don’t want anyone to feel the criminal investigation the police are conducting isn’t robust.”

She said her government would seek legal advice this week before considering the establishment of a commission of inquiry.

“If the police are able to publicly provide to the community in five months’ time about everything they’ve uncovered … that is a positive for the community because any commission of inquiry would take at least six to 12 months,” Ms Berejiklian said.

“We will not be leaving a single stone unturned.”

NSW Police Commissioner Mick Fuller said he was willing to release all findings to the public if permitted, and that authorities had interviewed 200 witnesses over the weekend.

He said COVID-19 testing was still underway for crew members on the ship – which is docked at Port Kembla – and daily conversations were taking place with NSW Health on moving the ship.

Once NSW Health gives the all-clear on the health of crew members, Mr Fuller will ask the ABF to instruct the ship to return to its port of residence.

Authorities have evacuated an additional 11 infected crew members from the ship to Sydney health facilities.

The commissioner on Monday said the disease was most likely spread on board by an ill food handler.

NSW Health Minister Brad Hazzard, meanwhile, on Monday said it was “unfortunate” 2700 passengers boarded the ship at a time when the coronavirus pandemic was already front and centre in the community’s consciousness.

“It is a very unfortunate outcome but at the time that that ship sailed, which was March 8 from memory, there was COVID-19 well and truly,” Mr Hazzard told reporters.

-AAP