The Australian Border Force (ABF) has confirmed it received a concerned phone call from the state port authority about the Ruby Princess, hours before the cruise ship was due to dock.
The NSW Port Authority contacted the ABF in the early hours of March 19 and expressed "concern in relation to the health of the passengers".
The ABF said in a statement on Wednesday the cruise ship was cleared to dock by NSW Health.
"The ABF officer made internal enquiries and subsequently advised the NSW Port Authority that the vessel had been cleared by NSW Health," an ABF statement said.
A report from Nine newspapers said the ABF officer instructed a Sydney harbour master to allow the ship to dock.
The ABF clarified it "did not seek to shape or influence any view or decision by the NSW Port Authority".
"This is not ABF's role," the statement said.
The Ruby Princess has been linked to multiple clusters of coronavirus cases in NSW and interstate since its 2,700 passengers alighted the ship without proper isolation protocol in place.
Fifteen deaths and at least 600 cases of COVID-19 have been officially linked to the cruise liner, meaning it is the single biggest source of coronavirus infections in Australia.
When asked about who bore culpability last month for the ship docking in Sydney, NSW Premier Gladys Berejiklian responded "all of us have to take responsibility".
But on March 25, ABF Commissioner Michael Outram said the NSW health department had given the green light for passengers to disembark, despite several people on board being tested for coronavirus.
"The Department of Agriculture officials advised my officers that NSW Health had conducted a risk assessment, had rated the risk as low and that health officials would not be attending the vessel," he said.
"As a result of that information, all of the passengers were given a green light to disembark."
Earlier this week, NSW Police Commissioner Mick Fuller announced the commencement of a criminal investigation into the communications and actions that led to the ship's docking and disembarking.
More than 30 officers from State Crime, Counter Terrorism and Special Tactics and Marine Area Commands have begun investigating the Ruby Princess debacle.
Investigators will interview high-priority witnesses in coming days, but they urged those with relevant information to contact Crime Stoppers.
