National Parks and Wildlife Service is coordinating the habitat restoration project along a 1500 metre stretch on Kooragang, which is home to one of the last remaining populations of the species in the Newcastle area.

"Frogs in this area were greatly affected by low rainfall, so the idea was to enhance their habitat through plantings and weed removal and make it easier for them to move across the landscape and access the available wetland habitat across the island," NPWS bush regeneration and volunteering officer Boyd Carney, who leads the project, said.

"Luckily, we did get some rain, and this has greatly benefited the frog populations and improved the odds of survival.

"Volunteers play a major part in threatened species conservation, not only with their contributions to on-groundwork, but also in other ways, such as reporting sightings of threatened species which help researchers track what is happening with species over time.

"They bring so much energy and passion to their work, and their efforts are much appreciated."

Volunteers are involved in the project through Local Land Services Hunter.

Dave Kennedy was retired and looking for something to keep him active when he became involved in 2017 through Conservation Volunteers Australia. While the organisation has since closed its Newcastle office, Mr Kennedy kept volunteering - even heading out on his own to remove weeds through the COVID-19 lockdown.

At 66, Mr Kennedy said he had seen the increased pressure on bushland and how much it had degraded over time.

"I'm aware of how much our bushland has been choked out by weeds, so it's heartwarming for me to see natives come back again," he said.

Bree Harding became involved earlier this year after starting a TAFE course in conservation and land management.

She said being younger, she was part of the generation that needed to focus on the future of the natural environment.

"I'm really quite passionate about anything to preserve what we have," she said.

While neither Mr Kennedy not Ms Harding have seen a bell frog on the island, they said it was very rewarding when they heard the frogs call when working on the site and saw other animals such as snakes and lizards that signified frogs were around.

The planting part of the bell frog project is almost complete, but the group will continue to maintain the site over time.