A police forensics team classed about two-thirds of the images on the more serious end of the child exploitation image scale.
More than 1000 images were also considered "age difficult", where there is some doubt the people in them were underage.
Court records show Kiddell was first convicted in 1978 of obscene exposure.
Wilful exposure convictions followed in Australia in 1986, 1989 and 1990 - offending that Kiddell claimed stemmed from his participation in a nudist community.
In 2011, a jury in New Zealand found him guilty of masturbating at a beach in front of a teen girl who was swimming there, but he fled to Australia before he was sentenced.
Four years later in 2015, an Australian court sentenced him to eight months in prison for masturbating in front of a nine-year-old girl at a swimming pool, asking her to touch him and grabbing the child as she swam away.
He was deported to New Zealand after his release, and sentenced to intensive supervision and community work for the 2011 guilty verdict.
He was convicted again in 2016 after he tried to groom a police officer who was posing online as a 13-year-old girl in the Philippines.
During the investigation, police found child exploitation images and videos on Kiddell's computer, resulting in a two-year sentence for possession of objectionable material.
Upon his release from prison in 2017, he was put under an extended supervision order - special release restrictions reserved for offenders believed to pose "a real and ongoing risk of further sexual or violent offending".
Kiddell was under this supervision order when he committed his latest child pornography offences in 2020.
In court today, his lawyer Antonio Spika asked the judge to consider home detention, saying Kiddell has started "extensive rehabilitation" since February 2021, even before these charges were laid.
His offending is linked to abuse and trauma he suffered as a child, and he has now been diagnosed with an impulse disorder, the lawyer said.
He is medicated, goes for weekly counselling, and has shown genuine remorse, Spika said, referring to a letter Kiddell wrote to the court and his regular donations to a children's charity.
However, Police prosecutor Lucy Na said jail was the most appropriate sentence given the serious sexual offending and relevant previous convictions.
Judge Fitzgerald said Kiddell's efforts deserved credit but this was offset by his relevant convictions in Australia.
He said Kiddell has been assessed as being at high risk of re-offending and harm, and recommended he continue his rehabilitation and join the Te Piriti sex offender treatment programme.
The judge also noted several positive letters of support from Kiddell's church group and community, a handful of whom were sitting in the public gallery for the prolonged sentencing, split into three hearings over the course of the day.
Kiddell turned to nod at his supporters before he was taken away by security officers.
