The government has recently opened tender for the more than half-a-million-dollar project to protect the mammal, which became the capital's official mammal emblem by popular vote last year.

The 35 wallabies that call Tidbinbilla Nature Reserve home were part of a successful breeding program that started with just three wallabies in 1996.

Before then, the last southern rock-wallaby had been seen in the wild was 1959.

Tidbinbilla's senior wildlife officer Jenny Pierson said having more wallabies allowed them to look at different ways of reintroducing the species to the wild.

"It's basically insurance," Ms Pierson said.

The future 120-hectare site was carefully chosen to ensure it contained enough rock formations to house different groups of the wallaby.

Because they live in harems, with one male and a group of females, dumping all the wallabies in the one site with one rock formation would see groups collide, Ms Pierson said.

But the huge site would also allow the staff to take a more hands-off approach with the breeding program, with hopes to build a 100-strong population inside the enclosure.

"We literally could not raise 100 wallabies in captivity," Ms Pierson said, pointing to the huge resources that would be required in terms of time, staff and money.

This way, conservationists can put the critters in a natural environment where the young learn to fend for themselves in an environment free from most predators, which include foxes and feral cats.

The fence will be similar to the one protecting wildlife at Mulligan's Flat Reserve, home to a plethora of indigenous species including eastern long-necked turtles, echidnas and the jet-black Canberra species of the shingleback lizard.

The $630,000 project brought in a huge range of organisations, including the ACT government and Zoos Victoria.

The zoo contributed the bulk of the funding with $430,000 with plans to use Tidbinbilla's future population of rock-wallabies for local recovery efforts.

But it's also about creating more genetic diversity, hailing from only three wallabies originally, Tibinbilla's population is also facing the issues that come with inbreeding, Ms Pierson said.

The ACT government threw a vote for the capital's mammal emblem last year after realising it was the only jurisdiction without one.

The southern brush-tailed rock-wallaby won by 40 votes over the eastern bettong, a species which was once extinct on the mainland.

Tidbinbilla now homes 70 bettongs, homed in a predator-proof enclosure similar to the one planned for the wallaby.