Andrew Alan Williams, 54, and his former partner, Laken Maree Rose, 32, have been sentenced in the High Court at Rotorua.
Williams was sentenced to 23 years and five months in prison, with a non-parole period of nine years and four months.
Rose has been given a jail sentence of 19-and-a-half years, with a non-parole period of seven years and nine months.
Williams was convicted on 56 charges and Rose 55.
They covered a raft of charges including rape, sexual violation, and making and possessing objectionable videos.
Police said the offending by Williams and Rose has had a horrendous impact on the victims and their families.
Detective sergeant Darryl Brazier said while nothing could reverse the terrible ordeal the victims and their families had suffered, he hoped that the sentencing today helped provide a small measure of comfort to them.
"This outcome is a great result for the team of hard-working investigators who worked tirelessly to hold these offenders to account," he said.
"During this complex and difficult investigation, they were exposed to a huge volume of distressing material, but remained focused and professional throughout.
"This is also a great result for the community who can be assured that these offenders are being held to account through their conviction and sentencing.
"Most importantly, this is a great result for the brave young victims and their families, who had the courage to talk to police and help bring these dangerous offenders to justice."
Brazier said that he had no doubt that had the families not come forward when they did, Williams and Rose would still be in the community offending against vulnerable young children.