The uncertainty comes as Radford College says it would be forced to run its own dedicated user-paid bus service for students if the new network goes ahead.

Principal Fiona Godfrey blasted the ACT government over the lack of communication on the delays and said she only learned of the April rollout through The Canberra Times.

On Friday, The Canberra Times reported the government would begin the controversial, revised bus network on April 27, at the start of the second school term in 2019.

The government has said delays to the light rail caused delays in the rollout of the new bus network, but Transport Minister Meegan Fitzharris's spokeswoman refused to speculate whether this meant the light rail would not go live until late April.

Ms Godfrey said she had tried to contact Ms Fitzharris repeatedly about the changes directly.

She said the college had not been consulted about the rollout nor the delay, with the independent school now set to lose its dedicated bus service in the new network.

The school had attempted to contact Ms Fitzharris after being unhappy with Transport Canberra's consultation over its dedicated service being cut.

Ms Godfrey confronted Ms Fitzharris on Canberra radio about the lack of bus services from Canberra's south to the school in Bruce.

Ms Godfrey said they had had no communication with Ms Fitzharris's office, but a spokeswoman for the minister denied this.

She told The Canberra Times the school was now looking at running its own bus service if it was unsuccessful in lobbying the government.

Ms Fitzharris's spokeswoman would not comment on whether there would be further delays to the new bus network's launch if the light rail was delayed further.

"It's optimal to have the light rail running before or at the same time," her spokeswoman said.

Ms Godfrey said parents paid to use the current dedicated bus and the college simply wanted that service to stay in place.

"To be clear, we are not asking for special treatment, nor are we asking for a free school bus service," Ms Godfrey said.

She said anybody who came to the college needed a working with children check, and with the loss of the dedicated service, young students might be at risk on buses or at interchanges with adult strangers.

On the other side of the capital, St Mary Mackillop College Canberra principal Michael Lee said he had spoken to Ms Fitzharris for 40 minutes on the phone about the new network.

"The initial draft that was put out was a hand grenade for many families," Mr Lee said.

He said parents had protested against the changes, after which Ms Fitzharris rang him directly.

"My community strongly advocated against the original bus routes, and [was] listened to," he said.

He said the school had kept its dedicated service but, with some services being redirected, some parents would still be inconvenienced.

Mr Lee said he was very sympathetic to any school or family who would have their mornings disrupted or were concerned about their children's safety on non-dedicated services.

It was important children could get to school on time to learn and eventually give back to the broader community, he said.

Opposition transport spokeswoman Candice Burch said the delay in the bus network raised questions about delays to the light rail, which the government is now promising will go live some time in the first quarter of 2019.

"It's still not clear whether the light rail is going live in April or whether it's going to be a staged approach," Ms Burch said.

But she said the biggest issue was there were still no timetables available to allow Canberra schools to start planning for the new network.

"If they can't get timetables, they can't get through that [consultation] process with their school community," she said.