NSW girl forced to smash her way out of bus

A five-year-old girl kept her wits about her when she found herself locked in a school bus in Sydney's west, using the emergency hammer to smash her way out.

Ruby Thorsby was the last one on the bus, but the driver forgot to drop her off and then forgot she was even on board.

She was left in the locked bus in a carpark of an after-hours school centre at St Clair.

Even though she was scared, she knew what she had to do to obey her foremost thought - "Go home, go home".

Ruby crawled through broken glass before jumping about 1.5m into the carpark where she was found and returned to the centre.

"Good it wasn't a stranger who would take me away," she said.

Her father Peter said he was "very upset" with what had happened.

The centre said the staff member responsible had now resigned.

"What happened was regrettable and we are deeply concerned," the centre said in a statement.

Mr Thorsby urged other parents with young children to teach them what to do in a similar emergency.