A teacher was falsely accused of indecently assaulting schoolgirls by boys who were unhappy that he had yelled at them in class.

Two intermediate school students admitted they made up the allegations, during a six-day jury trial in the Auckland District Court.

The teacher has lost his job, and says his 40-year career "is in ruins", Fairfax reported.

The teacher, who has name suppression, was on trial for seven charges of indecent assault at his Auckland school.

The Crown alleged the teacher had inappropriately touched three girls in his class, each aged 11 years.

"The defendant stroked the students' hair in an indecent manner, swiped his hand over the chest area of two of the victims and grabbed the breasts of another victim," prosecutor Jo Murdoch had told the court.

But one of the girls admitted she lied and the teacher had never assaulted her, when cross-examined by defence lawyer Marc Corlett QC.

She said she had also lied about seeing the teacher assault any other student.

She had later confessed the lies to her mother.

"I was an idiot," she said.

"My friend told me that she got touched and I pretended to believe her."

A boy who claimed he witnessed the indecencies, admitted there was a plan to make up stories about the teacher to get him fired after he told them off during class, Fairfax reported.

"I joined in because my friends were there and I wanted to support them and because I didn't really want to put up with any of that other stuff," he said.

The two other girls continued to claim they had been indecently assaulted and the Crown said there was no evidence of collusion between the students.

The jury took less than an hour to find the teacher not guilty on all charges.

The teacher admits that on March 23, 2017 he lost his temper in class after students began painting their hands and arms black.

He swore at the students, and there was a tense standoff in the classroom.

Corlett said that was when the students devised a plan to get the teacher fired. Within days they had made their complaint to a fellow teacher and police began investigating. The teacher was charged in July.

Speaking outside court, Corlett told Fairfax that it was clear the accusations were false.

"It was obvious from the video interview ... conducted by the police of two of the complainants and two so-called 'eye-witnesses' that their stories were hopelessly vague, inconsistent and implausible.

"They were irreconcilable with each other.

"Hundreds of hours of police resources and six days of jury time were wasted getting to what were inevitable not-guilty verdicts – all of which could have been avoided had the police approached the allegations with a healthy scepticism instead of swallowing whole what were obviously false accounts."

The teacher, speaking after he was cleared of the charges, told Fairfax his dismissal and the months since had been his worst nightmare.

"After 40 years as a teacher, and 27 years at this school I was dismissed within a few days of the allegations being made - allegations which have now been shown to be false, and deliberately made to get me fired," he said.

He said it had been a "terrible ordeal" despite having support from family and friends.

"It was devastating to sit in the dock while listening to one complainant admit she had lied, while another one admitted there was a plan to make up stories to get me fired.

"Their plan worked. I now have to try put back together the pieces of my life."

Detective Senior Sergeant Geoff Barber said it was disappointing when members of the public became victims of untruthful accusations.

"It is important that police take allegations of indecent assault against any person seriously, especially those involving children," he told Fairfax.

"Police are obligated to act on the information presented to us at the time a complaint is made and based on the information available, police took the appropriate action."