Pilots and aircrew will be doing a number of training exercises in Black Hawk helicopters over Parramatta today.
The Defence Force said the exercise ensures pilots and aircrew are well trained for flying in all conditions across urban and rural areas.
Flights will occur during the afternoon and evening and will normally not extend later than 11.30pm.
The Army will aim to minimise disruptions during the training, which has been designed to have as little impact on residents as possible.
However, some flight paths are lower than normally used and noise will be noticeable for short periods.