A woman who was working at the centre at the time told the court she saw Abraham grab sticky tape from the centre's office and put it over a girl's mouth.
Jennifer Wong, who broke into tears on the stand, said the girl was yelling as she played outside.
"Lynn came out and says, 'Can you stop it or I'll put tape on your mouth.' "
When the girl continued to be loud, Abraham allegedly went outside and taped the girl's mouth shut.
"We just looked at each other because we were shocked," Wong told the court.
She said she was so shocked she couldn't sleep.
As prosecutor Brian Dickey asked Wong about another incident when Abraham allegedly smacked a boy, the former childcare worker was overcome with emotion.
Through tears, she recalled Abraham telling the toddler he had "nothing to cry about".
She then broke down and said "I can't do it" and buried her face in her hands and wept.
Judge June Jelas adjourned proceedings so Wong could compose herself.
After the break, Wong said Abraham once gave a boy a "big smack on the bum" so hard that she could hear it. He started crying "very loudly".
Although they were concerned, she said "nobody said anything".
A number of the charges were similar in that the children got smacked on the hand, bottom or thighs when they allegedly didn't follow Abraham's instructions.
Dickey told the jury a 4-year-old who "would swear a lot for a young child" had his mouth washed out with soap by Abraham after he called another teacher an "ugly b****".
She allegedly told the centre's owner: "It was punishment for the language he was using". She received a warning.
Other staff also observed Abraham force-feeding children, including one as young as 1-year-old.
Dickey said the law was clear: Force cannot be used for the purposes of correction or punishment on a child.
The offending was only uncovered when a Ministry of Education employee was working part-time at the centre and saw Abraham's treatment of the children, then reported it to her boss.
An investigation was launched and afterwards the charges were laid, Dickey told the court.
Abraham's lawyer, Graeme Newell, opted not to do an opening address.
The trial continues.