WWII artillery found in Sydney's northwest

A fully intact WWII artillery device found by road workers in Sydney's northwest has been removed by defence personnel.

Galston Gorge was closed in both directions by police in the early hours of Thursday so the unexploded object could be removed.

Police Inspector Ian McCarthy told 2GB Radio the 25-pound WWII artillery ordnance was discovered about 500 metres from the Galston Gorge Road bridge by road workers.