A bus driver for a construction firm shot six workers dead and wounded six others as he sprayed passengers with gunfire near the Egyptian capital.

A police investigation showed the shooting on Tuesday was due to a row between the driver and some of his colleagues who were excavating near his house looking for antiquities, a security official said.

"Six employees were killed and six others wounded before the other workers were able to overpower [the driver]," provincial governor Fathi Saad said on public television.

The governor said the violence was all the more shocking because the driver had "a good reputation."

The driver for the company Arab Contractors was taking 22 employees to their workplace in Giza when he stopped the bus at Meniel Shiha, 20 kilometres south of Cairo, and started firing.

Arab Contractors, one of Egypt's biggest building firms, said the incident took place about 200 metres from one of its sites.

"The passengers were shocked to see driver Mahmud Taha Ahmad Sueilem, 54, pull out an automatic weapon from under his seat and start firing indiscriminately on the passengers," it said in a statement.

The official MENA news agency, quoting a security official, said the driver opened fire following a row with colleague and neighbour Abdel Fattah Salem "over archaeological excavations."

The official, citing the results of a police investigation, said that Salem and other company employee were involved in excavations near the driver's house in search of antiquities.

"Salem criticised them about this and they made fun of him and threatened him... The bus driver decided to get his revenge and hid an automatic rifle in the bus," the official said.

Survivors said earlier that the driver, who was arrested by the authorities, had been suffering depression due to a job transfer.

- AFP