Detectives clad in hazmat suits have raided the Ruby Princess cruise ship and questioned its captain and crew about how hundreds of passengers were allowed to disembark in Sydney last month.

The late-night raid came after a 62-year-old South Australian woman who had been on the recent Ruby Princess voyage died from the coronavirus, bringing Australia’s death toll to 50.

NSW detectives boarded the vessel at Port Kembla on Wednesday night, in a sign of a rapidly escalating criminal probe into the docking of the US-owned ship.

They seized evidence and questioned crew members to try and get to the bottom of how the vessel became linked to hundreds of COVID-19 cases and more than a dozen deaths across Australia.

“Strike Force Bast investigators are conducting inquiries on board the Ruby Princess this evening,” NSW Police said.

“The operation is being conducted under the strictest health and workplace safety guidelines.”

In coming days, police will interview other high-priority witnesses about the scandal. The vessel is expected to remain at Port Kembla for 10 days with 1040 crew members having medical assessments.

About 200 crew have shown symptoms of coronavirus, while 18 have so far tested positive.

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NSW is flattening the coronavirus curve

New COVID-19 infections continue to stabilise with NSW recording 48 new cases on Wednesday, taking the state’s total to 2734.

There are 36 people in intensive care and the death toll remains at 21.

NSW Premier Gladys Berejiklian welcomed the ongoing stabilisation and decline of new cases but warned community transmission was still increasing.

She said that while social distancing would be necessary until a coronavirus vaccine or cure is found, restrictions are being reviewed on a month-by-month basis.

She reminded people to adhere to restrictions, which are having a positive effect, as authorities keep a watchful eye on increasing community transmission.

The number of new cases has fallen to single digits in several other states and territories.

Nine new cases were confirmed across Tasmania on Wednesday night according to the public health department, taking the state’s total number of infections to 107.

Three of those are staff at either the North West Regional Hospital in Burnie or the neighbouring North West Private Hospital.

Four cases are patients who recently received care at the NWRH or NWPH. Twelve staff at the NWRH have previously tested positive to the virus, as have two inpatients.

South Australia reported another five cases of the coronavirus on Wednesday, taking the state toll to 420.

Sixteen people were being treated in hospital with seven of those in intensive care.

-with AAP