The almost 300m-long ship remained in Port Chalmers until late yesterday as authorities carried out their investigations into the death of the crewman, who died after a nitrogen gas cylinder exploded about 4.45pm on Thursday.
Investigations by police, Maritime New Zealand and the Transport Accident Investigation Commission are under way, with the ship sailing at 9.08pm once investigators were finished on board the vessel.
A Maritime New Zealand spokesman said it could be weeks before the maritime watchdog decided whether to prosecute in relation to the incident.
The Crown entity had powers under the Maritime Transport Act and the Health and Safety at Work Act, and was investigating potential breaches in relation to both.
"There’s still the last couple of interviews being done," the spokesman said yesterday afternoon.
"Once they are done there will be decisions as to what actions, if any, we will take next."
A spokesman for the Transport Accident Investigation Commission said two investigators arrived in Dunedin yesterday morning and concluded their interviews before the ship sailed.
The ship was headed to Sydney but would be in Wellington in a week if further interviews needed to be conducted, he said.
"We have conducted all the interviews that we think need to be done and secured some evidence from the incident site," he said.
"Our principal role is to investigate the circumstances and causes of an accident, with a view to identifying safety lessons for the industry.
"It’s all about learning lessons from this to avoid repeat occurrences," he said.
A police spokesman said officers completed their scene examination of the ship on Thursday night.
Police were investigating on behalf of the coroner.
Carnival Australia corporate communication manager David Jones said the cruise operator would not be commenting at present on what caused the gas cylinder to explode.
"It is not appropriate for us to make any comment at this time on the precise nature of the incident as it is a matter for the inquiries currently under way," he said.
"We are working with all relevant authorities and assisting in their inquiries. This involves both external authorities as well as our internal review which has already begun and we will of course await their outcome."
Carnival Australia had taken "urgent steps" to offer support to the dead crewman’s family.
"Out of respect to our crew member’s family and friends, we will not be commenting further in this regard," he said.
