An investigation is underway after an Australian Army Black Hawk helicopter was forced to make an emergency landing during a defence training exercise on Sydney Harbour.

The Black Hawk helicopter was on a counter-terrorism training drill over the harbour on Wednesday afternoon when it’s understood to have clipped a defence-leased ferry.

It was forced to make an emergency landing in a public park in Watsons Bay, with footage showing damage to several of the Black Hawk’s rotor blades.

Investigators inspect the chopper’s damaged blades. Photo: ABC

A Defence spokesperson said no civilians or defence personnel were injured.

The aircraft remained at Robinson Park overnight under guard to allow engineers to conduct further inspections and seek technical advice as part of the investigation.