Eight of the offenders have supervision orders. All of the offenders will have DNA samples and fingerprinting done today.
Corrections northern commissioner Jeanette Burns said the offenders would be monitored very closely today. Police and the Ministry of Social Development would help them settle into the community, she said.
Corrections have provided transport for the offenders and some housing. Some offenders will be staying with family members.
The offenders arrived just after 10am.
None of them are in custody.
Ms Burns would not comment on the offenders criminal pasts, saying it was a "privacy matter".
The offenders will be "processed" for the next hour. Police would make the call how they would be moved through the airport.
Tims confirmed all 12 detainees were from Christmas Island. The detainees were seen wearing handcuffs as they left the plane. Tims would not comment on if it was necessary to cuff the detainees but said police were committed to ensuring the safety of the detainees and the safety of the public.
Parliament passed legislation under urgency this week to ensure offenders deported back to New Zealand could be put under similar supervision conditions as parole for New Zealand prisoners.
Police assistant commissioner Malcolm Burgess said the priority was community safety. Although Australia had provided information about each offender under the information sharing agreement, at the airport they would be required to provide identity information and fingerprints, as well as a DNA sample. If that was not taken at the airport, they would be issued a compulsion notice to provide it at a later date. Police will also individually interview them to assess the best management regime.
Corrections was responsible for the supervision regime and would set out the offenders' obligations at the airport as well as arrange transport and accommodation if it was required alongside prisoner rehabilitation service PARS. Other government agencies, including the Ministry of Health and Social Development, would also be called on if required. Corrections was also responsible for ongoing monitoring of the offenders and responding if there were issues.
Ms Burns said government agencies were working together to ensure a "smooth arrival." "While there has been some focus on the group arriving this week it is important that this is viewed in the context of up to around 12,000 releases from the New Zealand prison system each year."
Labour has slammed the Government for being much too slow to react to an Australian law change made a year ago, which saw non-Australians who were sentenced to a year or more in prison automatically lose the right to live in Australia.
The new law also gives the Australian Immigration Minister the right to deport someone deemed to have failed the "good character" test.
One of those being held, Ngati Kanohi Te Eke Haapu, also known as Ko, a former New Zealand soldier who guarded Prime Minister John Key in Afghanistan, has been ordered out of the country on "character" grounds even though he has committed no crime.
Labour's Corrections spokesman Kelvin Davis said the detainees needed to be supported so they could integrate back into society. "That's the most important thing now. If they don't have food, accommodation and the other basics, they could fall back into crime, which is the last thing we want." Mr Davis had hoped to be in Auckland to meet the detainees but was unable to make it. "I don't know anything about the processes they've gone through today. All I can say is I hope steps have been taken to help them get on with their lives." Mr Davis didn't think it was necessary for the public to know where they were going or what they would be doing. "The last thing they need is the public pointing at them. They've done their time in Australia. They're entitled to privacy."