Rangers say picking up a walking stick during a bush walk may seem harmless but it's causing significant damage to the environment.

When hiking through a national park, it may seem harmless to pick up a stick from the bush and use it as a type of walking aid.

“The sticks are used by the little creatures [and plants] of the national park, the echidnas burrowing underneath it … insects, lizards, birds, fungi and moss.”

“The removal of just one stick can impact these animals in lots of different ways.”

He said 75,000 people visit the national park every year and hikers picking up sticks as walking aids can become an “ecological nightmare” when done in volume.

“Every stick will either be habitat or food for organisms.”

“I think a lot of people might just be thinking ‘it’s just one stick’, but they don’t see the sheer number of sticks that we are picking up and having to redistribute and put back into the bush.”