Police in the state of New South Wales (NSW) said in a statement on Saturday night that emergency services were called to reports of a light plane crash in the ocean near the town of Nambucca Heads, approximately 400 km north of Sydney, at 4 p.m. local time, Xinhua reported.
"The pilot and passenger of the aircraft died at the scene and are yet to be formally identified," NSW Police said.
The Australian Broadcasting Corporation (ABC) reported that the wreckage was found about 1.5 km off the coast.
Water police, ambulance crews and a rescue helicopter were deployed to the scene.
Fire and Rescue NSW Superintendent Grant Rice told the ABC that debris had washed up along the shoreline.
NSW Police said it has commenced an investigation into the circumstances surrounding the incident, with the Australian Transport Safety Bureau (ATSB) assisting.