If it could express itself like a human, this koala would breathe a sigh of relief.

The newly unveiled national park it lives in spans 962 hectares along the Georges River in south-west Sydney.

Named after how the local Indigenous population refer to this area, the Warranmadhaa National Park was opened in July to protect Sydney's largest koala populations.

The plan is to progressively expand the protected area to 1,830 hectares through further land acquisition.

The State government says the idea is to balance the protection of the koala habitat with the construction of 73,000 new homes in the area.

But koala advocates say the plan falls short of its promises.

Fences and underpasses to help wild animals cross the notoriously deadly Appin road are yet to be completed.

They will allow access to other habitats and breeding grounds which are essential to keep the population healthy.

But a disagreement between the developer and a landowner has delayed the work.

Stephanie Carrick, who manages the Sydney Basin Koala Network (SBKN), says that koalas are threatened by all sorts of developments such as mining, housing and logging.

"It's half of what has been promised and there doesn't actually seem to be a real plan on how they're (the State government) going to deliver the other half and how long it's going to take for them to do it. And even that the full park is still half of what was promised many years ago. So, what's happened now is 900 and something hectares of public land, habitat that already existed that was never going to be developed, has now been given to the national park system, which is a good thing," she says.

The timeline on the extension of the park is uncertain as it depends on land acquisition by the government which is not a forgone conclusion and could take years to happen.

Because of the elusiveness of the marsupials, a precise total population figure is hard to compile but according to the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the National Koala Monitoring Program (NKMP), their number in 2024 was between 95,000 and 238,000, spread between New South Wales, Queensland and the Australian Capital Territory.

There are also some populations in Victoria and South Australia which are not listed as endangered and estimated at between 129,000 and 286,000.

The last 2014 entry on the IUCN Red List of Endangered Species lists the koala as 'Vulnerable' with a decreasing population.

In 2022, the status of koalas, which are endemic to Australia, was changed by the Australian government from 'vulnerable' to "endangered.'

That means their protection level has increased.

There's also a newly created chlamydia vaccine that is bringing hope in the fight to eventually eradicate one of the major threats to koalas’ existence but hasn't proved as widely positive as expected for some experts.

Professor of Veterinary Pathology Mark Krockenberger from the School of Veterinary Science at the University of Sydney explains that he’s been studying koalas for the past 25 years. He’s observed that chlamydia can make the difference between a marsupial population expanding or becoming extinct, all within 10 to 15 years.

The koala population protected by the new park, in its northern part, is the state's only chlamydia-free colony in Sydney's south west.

Because it’s free of the disease, that population has a high fertility rate and is expanding.

"As that population expands, it's starting to come into contact with populations to the south of Sydney and the southern highlands of New South Wales that does have chlamydia present. And so, the threat to chlamydiosis entering this population and having a dramatic effect on this population is high," explains Krockenberger.

The disease specialist explains that preserving the koalas’ habitat is only one aspect of the protection of the species.

Mitigation strategies to avoid chlamydiosis entering healthy populations is what his team has been focusing on in the past five years.

And in his experience, vaccination isn’t sufficient as the sole tool in preventing chlamydiosis entering healthy koala populations.

“Koalas need a very specific habitat, certain types of eucalypts that they thrive on. So, anything to preserve habitats such as national parks is very valuable, particularly when there's pressures of urban expansion from the Sydney population. So, I think that's really important to make sure that koalas have got somewhere to live. We're very lucky to have these animals so close to Sydney," he says.

One of the active strategies Krockenberger’s team is focusing on is how to manage koalas on the edge of the healthy population that might be coming into contact with Chlamydiosis and how to avoid them getting into the Chlamydia-free population.

A suggested solution is to identify the positive animals and treat them with medication.

Krockenberger and his team have also been involved in a New South Wales government program called “Sentinel” that’s looking in detail at a number of koala populations around the state to allow for a baseline health assessment of the marsupials.

Over the past 18 months, his laboratory has processed hundreds of samples to detect different agents of disease that are affecting koalas.

An initiative that could prove useful in the not-too-distant future for koalas’ well-being.

AP video shot by: Albert Lecoanet