The annual aerial patrols are being conducted to inspect the electricity network for potential bushfire hazards.

Two helicopters have been contracted to inspect bushfire prone parts of the Hunter, Central Coastand Sydney.

On Wednesday and Thursday, helicopters will fly above areas including Rutherford, Bolwarra, Lochinvar and Morpeth.

Other areas including East Maitland, Thornton and Largs will be inspected later this month.

The helicopter flights are the safest and most efficient way to inspect high-voltage powerlines and Ausgrid will remove or repair any hazards identified on our network during and soon after the patrols.

"The patrols reduce safety risks for our own people, because by using a helicopter, we can identify potentially dangerous hazards from above without putting our workers at risk," Ausgrid Chief Operating Officer Trevor Armstrong said.

Crews will be in the air from about 7.30am to 5.30pm. Property owners may want to secure livestock during patrols.

"The helicopters fly between 15 and 35 kilometres per hour and have been modified to allow for the quietest possible operation but they may fly low at times, which can startle livestock in rural areas," Mr Armstrong said.

The flight schedule is available at: ausgrid.com.au/bushfirepatrols