The Defence Force is looking to add to its fleet of about 60 drones.

Some of the current 60 are obsolete and being withdrawn just four years after the military began buying drones, but new ones will be added.

It was aware of the cyber risk using the cheap Chinese-made Da-Jiang Innovations drones and never connected them to the Internet or its own networks, a Defence spokesperson said.

"DJI drones are only to be used for training support tasks and are not for operational use."

Police have judged the benefits of drones outweigh the risks of data being hijacked, and are looking to add to their own fleet of 26 drones.

Though most of its drones are from DJI, Defence also has a far more expensive Flir Skyranger and the army operates a single top-end AeroVironment Puma drone.

It was experimenting with these to see what it would need in future.

"All three services will be acquiring various types of drones for use in the coming years," the spokesperson said.

Drones helped identify threats and scenarios beyond the line of sight.

"Unmanned systems like drones and robots are ideal for the so called 'dull, dirty and dangerous' tasks to reduce burden and risk on our personnel."

It occasionally also used drones from external contractors for help with jobs like mapping.