Corrections chief executive Ray Smith. Photo / Mark Mitchell
The case has sparked a system-wide review looking at how he managed to get through border control.
A Department of Corrections spokeswoman said Willoughby had completed a sentence for unspecified drugs offences. She would not say how long he was imprisoned for but said it was "significantly less" than two years.
All released prisoners are subject to strict conditions which include regular reporting to probation officers and restrictions on living and working arrangements, she said.
A warrant has been issued for his arrest and Australian authorities notified. Department chief executive Ray Smith said Willoughby had legally obtained the passport he used for the trip.
"The department takes breaches of release conditions seriously and will be including this case in the current review in addition to the enforcement action already taken," he said.
"Last week I initiated an inter-agency review with police, the Ministry of Justice, Customs and the Department of Internal Affairs. A feature of this review will be how information between these agencies is shared."
New Zealand authorities were working with their Australian counterparts to bring Willoughby back to New Zealand, he said.
"It should be noted that immigration requirements in Australia require passengers to declare any criminal convictions on arrival."
A Customs spokeswoman said Willoughby used a valid passport and there were no alerts in the organisation's computer system to prevent him leaving.
Customs screened all passengers through risk assessment and profiling. This included a face-to-passport check and details being matched against the organisation' database, she said.
"If an alert placed by another agency is triggered, Customs responds according to the alert instructions which may include a referral to the relevant agency.
"If there is no alert the passenger is not stopped unless part of routine screening procedures," she said.
Labour Party Corrections spokeswoman Jacinda Ardern said it was "crazy" that a red flag was not raised when Willoughby presented his passport at border control.
"The question that we need to ask is, is there a process in place already? If there is then why is it falling down? If there isn't then it's nonsensical and needs to be rectified."
It is unclear whether the name on Willoughby's passport was the same he was charged under, or whether he used two names as Smith did.
"If we've got someone whose legal name and the name under which they were charged has managed to use a passport with that same name then that raises a whole set of extra questions," Ardern said.
Queensland police, New Zealand police and Internal Affairs Minister Peter Dunne declined to comment. Dunne referred inquiries to the Minister of Corrections who could not be reached for comment yesterday.
