It is understood the traveller flew yesterday from Rarotonga in the Cook Islands to Auckland.
They caught NZ175, an Air New Zealand flight from Auckland to Perth this morning, which took off about 10.30am.
The one-way bubble between the Cook Islands and New Zealand doesn’t require isolation on arrival but does require a stay of at least 14 days before transiting to another country.
However, that 14-day stay in New Zealand hasn’t happened.
About an hour into the flight, as the plane flew across the Tasman, the airline realised the man had breached the bubble and reported it to authorities.
Air New Zealand confirmed the incident in a statement this afternoon following Stuff breaking the news of the breach.
“We have been made aware of a passenger onboard NZ175 Auckland – Perth today who is ineligible for quarantine-free travel to Australia.
“We are working with the relevant authorities on both sides of the Tasman and will follow their guidance.
“The next steps for this passenger will be determined by the Western Australia authorities.”
The Ministry of Business, Innovation and Employment, which encompasses both Immigration NZ and the managed isolation and quarantine system, has been approached for comment.