A special needs student has been left on a parked school bus in Melbourne for a day in an "appalling incident" that has resulted in the driver and a supervisor being sacked.
The primary school student didn't get off the Crown Coaches bus at the Monash Special Development School last Thursday morning and was only discovered hours later when the coach returned for the end-of-school run.
The seven-year-old boy spent the day, during which temperatures reached 30C, on the bus parked at a Nunawading depot.
He reportedly snacked on his packed lunch.
Monash principal Helen McCoy said the student was thankfully "OK" following the ordeal.
An almost identical mishap occurred in June 2015 involving Crown and a student from Bulleen Heights School.
The Victorian education department is reviewing its arrangement with the bus company following the latest "appalling incident", a spokeswoman said on Friday.
"This was completely unacceptable and we are pleased the bus company has taken tough action against the driver and chaperone," Ms McCoy said.
"To make sure this doesn't happen again we are also now calling parents immediately when the child is believed to be absent."
Crown Coaches has apologised to the student, his family and the school, a spokesman told AAP in a statement.
The company says the incident was due to "human error rather than any systematic error".
"The driver and supervisor did not follow Crown Coaches procedures of post-service vehicle checks," the spokesman said, adding both were stood down immediately and then dismissed on Monday following an investigation.
A driver and supervisor were also sacked following the Bulleen incident in mid-2015 when a boy was left on a bus for almost six hours at the depot.
Crown Coaches subsequently changed its protocols so buses were meant to be checked after morning and afternoon school runs.
The company also started developing an electronic passenger manifest which is due to be introduced across the fleet in 2017.
It will use GPS tracking and record the time individual students get on and off a bus, the company said on Friday.
A mobile app will allow teachers and parents to monitor "the location of the bus and passenger status" in real time.