When the cruise ship Sea Princess called at the Port of Tauranga on Tuesday there was one passenger in particular who was not allowed on shore.

In fact he or she was confined to the cabin allocated soon after the stowaway was discovered, shortly after the Sea Princess departed Brisbane at the start of the current cruise.

The galah, a type of Australian cockatoo, was able to be captured and placed in a cabin – which saved its life, says Ministry of Primary Industries border clearance services manager, Andrew Spelman.

"The only way for the ship to enter New Zealand was to have the bird euthanised or secured and bonded to the vessel," says, Andrew.

The bird could have been carrying avian diseases with the potential to harm New Zealand's native bird population.

The cruise ship alerted the Ministry for Primary Industries about the stowaway as it approached Milford on January 25.

"We needed photographic evidence of its containment and the name of an officer responsible for looking after the bird. There was also a requirement for MPI officers to check on the bird and its containment facilities at every new port visit in New Zealand,” says Andrew.

"The vessel operators have been very particular in following our directive, so we're satisfied any biosecurity risk has been mitigated."

The story looks like it will have an even happier ending after the vessel leaves New Zealand this week, says Andrew.

An MPI quarantine officer was able to determine the cockatoo has a microchip that matches the number of a missing bird from Brisbane.

"We have word from Australian officials that it can be reunited with its owner in Brisbane when it returns home, as long as it passes an examination by a departmental vet."

The Sea Princess departed Auckland for Brisbane on Wednesday.