A man is charged over a road rage incident involving a school bus in Sydney's east, during which he allegedly retrieved a knife from his car.

A man has been charged after a road rage incident involving a school bus in Sydney's east.

A bus carrying 57 primary students and three teachers collided with a black Volvo sedan on Anzac Parade in Kingsford around 4:00pm (AEST) on Friday.

The students from a Matraville primary school were returning from an excursion.

Both drivers began to argue and police allege the 22-year-old driver of the car tried to force his way into the bus.

Inspector Stephen Eggbers said the bus driver tried to restrain him, and the two men struggled before things took a turn for the worse.

"He then went to his car and retrieved a knife," he said.

"The bus driver got back into the bus, locked the doors and drove off as the person was again trying to damage the bus. Police arrived and noticed the driver was affected by some type of substance."

Police searched the man's car and found a pipe for smoking the drug methylamphetamine, known as meth or ice.

He was sent for blood and urine testing before being charged with assault and damage to property.

The man was granted conditional bail to appear in Waverley Local Court on September 17.

Police said no-one was injured in the incident.