A Waikato woman and her former partner have received lengthy jail terms for a string of horrific sexual abuses of young children, including the rape of a child aged 3.

Laken Maree Rose, 32, was sentenced in the High Court in Rotorua today after being found guilty of 45 charges at her trial in the Hamilton High Court in December last year.

She also earlier pleaded guilty to 10 further charges.

Rose was sentenced to 19 years and five months' prison, with a minimum non-parole period of seven years nine months by Justice Matthew Muir.

Justice Muir said it was hard to imagine a "more egregious" sexual offending prosecution case and the words "sickening and depraved" came readily to mind.

Rose's charges included six counts of rape, nine of sexual violation by unlawful sexual connection, 16 counts of indecent assault, and seven of inducing indecent acts to be performed on a young person.

Laken Maree Rose appears in the High Court in Rotorua for sentencing today. (Photo / George Novak)

Rose was also found guilty of a total of five charges of making and possessing objectionable publications, and three of attempted sexual violation.

They related to four girls aged between 3 and 13 at various locations, including the Bay of Plenty, Palmerston North and the Waikato.

Rose also admitted nine charges of inducing a young person to commit an indecent act, in relation to a 14-year-old victim and a charge of knowingly making an objectionable publication, being a recording of a video showing the sexual exploitation of a girl aged between 13 and 14.

Laken Maree Rose, 31, on trial in the High Court at Hamilton in November last year. (Photo / File)

Rose claimed she was a victim of domestic abuse and had been compelled to participate in the abuses under duress from her ex-partner and co-offender Andrew Alan Williams.

She insisted Williams, 54, had threatened to kill her if she did not film him abusing the victims.

A psychiatrist gave evidence that Rose suffered from a dependant personality disorder.

However, Justice Muir said he found limited evidence of domestic abuse nor evidence of threats of harm by Williams in the more than 2000 texts he had reviewed.

Rose did not come across as fearful in the various video clips and never mentioned any abuse to a friend of 10-years and a police detective with the Hamilton CIB Child Protection Team, the court heard.

Andrew Alan Williams appears in the High Court in Rotorua for sentencing today. (Photo / George Novak)

Justice Muir earlier described Rose's sexual abuses of young children as "unbelievable and "utterly brazen".

Williams, who pleaded guilty to 55 charges on the day of his trial, was sentenced to 23 years and five months' prison, with a non-parole period of 9 years and four months.

His crimes were against seven children aged between 3 and 14, and which took place at various locations in the Bay of Plenty, Waikato and Palmerston North, between January 1, 2015 and March 10, 2019.

Williams' charges included attempting to sexually violate, indecent assault of a child, rape, sexual violation and inducing children to perform indecent acts.

Williams also admitted charges of possessing and publishing objectionable materials.

Rose and Williams' offending came to light in March 2019 while they were living together in Cambridge after a complaint was made to the police in Katikati.

Detective Sergeant Darryl Brazier of the Western Bay of Plenty Child Protection Team said the offending by Rose and Williams had a horrendous impact on the victims and their families.

Laken Rose and Andrew Williams were sentenced in the High Court in Rotorua today. (Photo / File)

"While nothing can reverse the terrible ordeal the victims and their families have suffered, I hope that the sentencing today helps 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 they were exposed to a huge volume of distressing material during the investigation, 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.

"I would like to thank them for the cooperation and the incredible strength they have shown throughout the prosecution, and my thoughts and support remain with them as they get through this horrific time.

"I have no doubt that had the families not come forward when they did, and police took the action required, these two would still be in the community offending against vulnerable young children."