Egyptian officials say a tour bus crash outside Cairo has killed six Australian tourists and injured at least 24 others.

Officials say a group of Australian police officers and their family members were on the bus, which crashed late Tuesday while on its way back to the capital from the port city of Alexandria.

The cause of the accident was not immediately known.

Fatal road accidents are common in Egypt - mostly due to bad road conditions and poor enforcement of traffic laws.

Some information for this report was provided by AP and Reuters.