The as yet unnamed baby makes the 14^th member of Tidbinbilla's koala population, where staff run a "hands-off" breeding program for the threatened species.

Once in their millions across Australia, koalas have been long extinct in the ACT with about 80,000 koalas at most believed to be roaming the continent today.

Tidbinbilla's threatened species program leader Nicole Hill said the joey's mum was Yellow, who shared her enclosure with male koala Jed, another female and her 18-month old joey Yulu.

"It is good news but we've kind of got a pretty successful breeding program for those koalas so we usually have joeys coming through every single year," Ms Hill said.

Koala joeys only start sticking their head out of ma's pouch at six months.

At 18 months, the small joey will be allowed to move from Tidbinbilla's smaller breeding enclosure to its larger 40 acre "Eucy" enclosure - short for Eucalyptus Forest.

"That's essentially just a free range patch of forest, it's just protected from foxes and cats by the fence," Ms Hill said.

But Canberrans can come visit Yellow and her joey now at Tidbinbilla.

"That way we can connect with the public and communicate about the status of these animals," Ms Hill said.

"We need the support of people out in the wider community to make a difference."

"They give us an opportunity to talk about these issues."

Ms Hill said koalas slowly separate with their joeys. They leave them in a certain spot and spend longer and longer periods away, until they don't come back.

Tidbinbilla staff mimic that by setting up spots in Eucy, bringing the joeys food until the staff too stop coming back.

The koalas at Tidbinbilla are mainly a breeding population but staff do small amounts of research, including testing the ranges of two younger koalas in Eucy.

"It's a very small data pool," Ms Hill said.

"They both have really stuck to that area where we've released them."

She said the older of the two had really started to explore the 40 acre - 16 hectare - patch, with male koalas in the wild having a 43 hectare range.

The staff feed Yellow and her joey every day, bringing them a variety of eucalypts.

"There's about 800 species of eucalypt in Australia and koalas Australia-wide only eat 60 of those," Ms Hill said.

"Our koalas have only six species they like. They're a highly specialised animal."

Ms Hill said different leaves had different toxicity levels and koalas, who actually had an acute sense of smell, could smell how toxic the eucalyptus was.

"We obviously can't tell that so we provide them with a variety of different levels," Ms Hill said.

Canberrans can visit the smaller enclosure and Eucy, which is also home to other Australian wildlife like the vulnerable long-nosed potoroo, southern brown bandicoots and swamp wallabies.

Ms Hill said it would be possible to find some still wild koalas just across Canberra's western border.