She said the defendant - who has name suppression - inappropriately touched both girls on more than one occasion in three different locations.
The complainants both alleged he violated them in his van on a trip between Dunedin and Gore on separate trips.
Yesterday, the court heard evidence from one of the girls, who said she did not want to be in the vehicle with the man.
She was about 9 years old at the time, and the man reached up her pants, touched her for around five minutes and then continued driving, she said.
She recalled him smiling and maybe chuckling afterwards.
“What you’ve described is impossible,” counsel Hugo Young told the witness.
The teary-eyed complainant denied that was the case.
Young said she was recalling a Mercedes van, which was not what the defendant was driving at the time.
“The seating arrangement was different... It had one less row because it’s a shorter vehicle,” Young said.
“I’m saying that... your description of the van is completely wrong.”
The witness said she may not have known what vehicle the alleged offending occurred in, but she was certain it happened.
Later in the trial, the second complainant is expected to give evidence that she confronted the defendant in 2019.
The court heard that text messages between the two show the defendant said it was the complainant’s actions that ruined her own life and that “she came on to him”.
Young said the defendant would take the stand later in the trial, which is expected to continue all week.