Jurors have been told a daycare centre manager was prompted to wash a child's mouth out with soap after the four-year-old called a teacher a "stupid bitch".
Lynn Abraham is accused of assaulting nine pre-schoolers in 11 separate incidents at Bright Minds in St Johns, and is on trial in the Auckland District Court.
It is alleged the 59-year-old smacked and force-fed children in her care.
The Crown says she taped shut one child's mouth and put soap in another child's mouth.
A former colleague, Santosh Vermula, gave evidence that the mouth washing incident happened at afternoon tea time.
"Lynn came out and said '[the child] said stupid bitch to Jennifer and I washed his mouth out with soap'," the woman told the court.
She said she had witnessed Abraham smacking children on their hands, but not on any other part of their body.
Ms Vermula said the noise was loud enough to be heard in a busy classroom.
Earlier, another colleague, Jennifer Wong, was challenged by defence lawyer Graeme Newell on the veracity of her evidence.
He suggested Ms Wong did not see Abraham place sellotape on a child's mouth, as described, and asked whether children were smacked, or merely tapped on the hand.
"If it was a tap the children wouldn't cry," she replied.
"It was a smack."
The trial continues.