The school is one of many across the territory where principals and parents are worried children's safety and learning have been put at risk because of sweeping cuts to dedicated school buses.

Instead, more students are being ferried through the public network, on what officials claim are faster, more frequent services.

At St Vincent's, the bus that once arrived outside at the end of the school day is gone.

Principal Lina Vigliotta now walks students seven minutes down the road to the new stop. Public services leave at 3:03pm and 3:14pm and do not come past again until 3:46pm so students must leave early to avoid a long wait.

Ms Vigliotta said the missed school time would add up to nine days over the course of the year.

Good Shepard Primary School principal David Austin caught a public bus alongside anxious students on Monday.

He said safety was the number one issue at the moment, with concerns children would be turned away from full buses.

"There was high anxiety and a few tears," Mr Austin said.

"It was full to the brim, we squished on and we've got little kids that can't even reach the handles. A couple of students from Amaroo tried to get off the bus but the driver didn't notice as it was so full - I had to yell [out] to make sure they got off."

Matthew Unthank had to pick up his 10-year-old step-son from a bus stop in Dunlop on Monday as the family were unaware their dedicated school bus had been cancelled.

Days earlier they had checked the stop to see if it would still be active.

A year two student "on the verge of tears" was also stranded at the same stop, and two buses drove past the children without stopping, Mr Unthank said. The child was seen safely home.

Another concerned parent told The Canberra Times her son was late to school after two buses drove past him because they were full.

"This is just unsafe for kids," she said.

"I did call Transport Canberra and he did assure me drivers had to pick up school children."

Transport Canberra confirmed buses at capacity must not drive past students but instead wait with children until alternative transport can be arranged.

Student safety was a top priority, a spokesman said, and customer service officers were out on the ground to help guide commuters.

At Merici College, while one public bus had failed to turn up there was also plenty of excitement as students boarded the nearby light rail.

Principal Loretta Wholley said Transport Canberra staff had been prompt at responding to issues but noted five new families had since signed up to the school's existing private bus service.

At St Edmund's, principal Joe Zavone said affected students were making the best of a bad situation but there had been some confusion since the new timetable came into effect.

Teachers had already called two meetings with students to clarify new routes and the school had produced a "cheat sheet" for staff quizzed about the network by students.

"This is something schools shouldn't have to do, communication about the changes should have been clearer," Mr Zavone said.