He was caught when a US deputy sheriff logged onto an internet filesharing website and found folders under the "babyrape'' user name.
The folders were traced to an IP address at Laing's West Auckland home.
The sheriff then contacted New Zealand Customs.
Judge Clare Ryan said Laing used his neighbours' insecure wireless internet connections to try to avoid detection.
The court heard he had been out of prison for only four months and was still under release conditions which forbade him from using the internet.
Judge Ryan said more than half the images were of adults sexually abusing babies and young children.
"I have had to view those images for the purpose of this sentencing and they are not a pleasant sight.''
Customs lawyer Gareth Bostock said child abuse victims were re-victimised every time their pictures were downloaded on the internet.
"This is actually the worst case of exploitative material to come before the court.''
He said one of the victims in Laing's pictures had been identified. She was aged between three and four when the photos were taken.
The man convicted of abusing her is serving a 50-year jail term in a US federal prison photos of her were found in Laing's possession after the man went inside.
Laing's lawyer Seonaid Abernethy said her client stored the images on a USB stick and flushed them down the toilet.
"He said all through this that he had simultaneous compulsions to do this while self loathing at the same time.''
She said Laing pleaded guilty at an early opportunity and has a "degree of insight into his moral collapse''.
In sentencing, Judge Ryan said she took into account that this was the fourth time Laing had been sentenced for similar offending, despite taking part in sex offender programmes in prison.
She said in August 2011 Laing was on parole and received a "positive report'' from the board that suggested he was complying with his sentence. He was also attending monthly meetings to deal with his problem.
However just a month later, Laing was caught with explicit child sex images again.
"He had all the help in the world and this still happened.''
Laing was recalled to prison to serve the rest of the five-year term he received in 2008.
Judge Ryan said today's five-year sentence - the maximum available - would begin in October, only after he finished the previous one.
She said the Probation service had assessed Laing as having a high-risk of re-offending and having low motivation to change.
Judge Ryan also ordered that Laing's laptop be destroyed.
Laing is a "sexual menace'' according to Denise Ritchie, the founder of lobby group Stop Demand, which campaigns against child exploitation.
"He is a sexual predator and to me, of all the cases over the years, he would have to qualify for some sort of preventative detention.''
She said Laing's case was the worst of its kind and he had never acknowledged the impact his offending had on the children.
