A resident, who did not want to be identified, said she found the group of around 20 girls from Carlton School walking on Alma Road near Moore Avenue on Monday around midday.
"As soon as I saw them I thought, 'What the hell?' There was no adult, there was no teacher ... there was no nothing," the woman said.
The girls told her they were delivering flyers and had been asked to return to the school as a group, but said a few girls who seemed to know the way had run ahead.
"There were two of them shaking and crying, and another group of kids wouldn't even let me talk to them - they must have been so good at stranger danger," the woman said.
"They weren't all right - they were bloody lost. One of the girls said they told the teacher they didn't want to be by themselves.
"It's shocking. If that was my kids I would not be happy."
The woman said she walked them to the back entrance of the school.
Carlton principal Gaye O'Connor sent a letter to parents and caregivers on Monday to explain the situation.
It said the girls were delivering notices to letterboxes in the area. There was some disagreement about how to return to the school and some girls began crying "after some scare-mongering was started by a girl".
There was also disagreement about the best route, the letter said.
"I had trusted the girls, as a group of senior students, to be able to manage this task, which most of them did. The girls have agreed that there was no real issue."
The letter did not explicitly say if the year 5 and 6 students were supervised or not.
The father of a girl who was in the group, who also did not want to be identified, said he had received the letter from the school and believed it matched up with what his daughter told him.
He had talked to his daughter on her mobile phone when they were delivering notices. She said she was with a staff member at the time and she was fine.
"I'm satisfied, as a parent who was directly involved, that the story checks out."
