It was also an issue in urban areas.
Williams and Cameron said they'd heard from bus drivers who were very uncomfortable that they got to wear a seat belt, but that protection was missing for the children riding behind them.
"In social media responses, people have told a lot of stories about when their kids were in a (school bus) crash, or when the bus driver had to put the brakes on really suddenly. Children sitting in that front seat have gone over the rails into the footwell, others have smacked their teeth, Williams said.
"Unfortunately, unless there's a fatality, it doesn't seem to count."
Cameron, a farmer from Waitaki Valley, said in her district she talked to a bus driver who won't put 5, 6 and 7-year-olds in the front seats.
"That poor bus driver feels responsible for their safety so she puts them further back so they won't fly through the front."
Cameron and Williams said they don't expect overnight change but want to see a plan for staged implementation.
That could start with the Ministry of Education requiring, from a given date, that any company tendering for a school route must use buses fitted with seat belts.
Jacqui Dean, who chaired Parliament's Petitions Committee, pledged to put it before MPs so information could be gathered and next steps decided.
"In my own district of North Otago, we've had buses slide off unsealed roads," Dean said.
"We'll get Philippa to Zoom in to our committee. I'm looking forward to hearing more from her and finding a way forward. She's pragmatic - she's a farmer!"