Transport for NSW worker by day, photographer and environmental science geek by night, Finlay thinks the high demand for his walk and talk was because many people think the glowing creatures are a rare find.

"I'm not holding a rock concert or anything, this is just fireflies," he told the Mercury.

"People don't realise we have fireflies in Australia ... they think they have to go overseas to see them.

"They see them in movies and TV shows and it's like this magical thing that they will never get to see here in Australia, but they are all over the place."

Finlay was forced to postpone his original event after 7000 people signaled they were interested just days after posting it in September.

He has since held a dedicated talk on the luminescent beetles at Dapto's Ribbonwood Centre last week and is this week scheduled to host six separate nature walk and talks (all sold out) along the Cascade Falls walking track.

"I want to educate people, I want to teach them about the do's and the don'ts," Finlay said.

"It's the males that fly, the females stay on the ground, which is why it's so important to stick to the path as you could be trampling the female fireflies.

"If you go clambering all over the bushland to see the glow worms or get closer to the fireflies, you literally are ... destroying them."

Finlay's love for glowing creatures - like sea sparkles, ghost fungi, fireflies and glow worms - came from his daughter when she was young, and her fascination for insects.

The love has grown so much that he and his friend Scott Kemp have discovered a new breed of millipede in the Illawarra, which also glows, and is yet to be classified by scientists.

"I hope they name it after Scott," Finlay said.

"Here are these creatures that have obviously been here for hundreds of thousands of years, but we're only now starting to notice."

If people want to learn more about glowing creatures, or when Finlay announces his next series of walk and talks, follow his Instagram page - @DavidFinlayDigital.