The move on Thursday came as part of a homicide investigation into the incident, which saw 2,700 passengers get off the vessel and is believed to be the country's deadliest infection source.
Investigators boarded the ship at an industrial port south of Sydney, interviewed the captain and took electronic logs as evidence, New South Wales (NSW) state Police Commissioner Mick Fuller said.
“They spoke to the captain of the ship, who was extremely helpful,” Fuller said in a televised news conference on Thursday.
“Ships have a black box very similar to that of international planes, and that and other evidence has been seized for further investigation.”
At least 15 Covid-19-linked deaths are tied to the Ruby Princess vessel - owned by Carnival Corporation & PLC - while hundreds of the passengers who disembarked have since tested positive for the virus.
In total, Australia has recorded roughly 6,000 coronavirus cases and 51 deaths linked to the pandemic to date.
In the past day, Australia recorded 96 new coronavirus infections, its first increase of less than 100 cases in three weeks, Health Minister Greg Hunt told reporters in Canberra.
“The curve continues to flatten, we are consolidating the gains,” Hunt said in a televised news conference.
“While we have been cautious over the last two weeks as we have seen the early data, what we’re seeing now is a genuine consolidation.”
Authorities are imploring people to stay home and cancel trips to traditional vacation spots over the upcoming long Easter holiday weekend, saying tight restrictions on movement could need to stay in place for at least six months.
The restrictions include a broad order for people to stay home except for essential work or to exercise and buy food, and police have said they will use the threat of on-the-spot fines to stop people travelling or socialising over Easter.
Seeking to limit the impact of the restrictions on the economy, politicians passed a wage subsidy programme late on Wednesday worth 130 billion Australian dollars.