Officials in Australia say a large housing development project could be blocked to protect endangered koala bears in one of the fastest-growing parts of Australia’s biggest city. The New South Wales government plans to create a sanctuary in Sydney to preserve the country’s last-remaining disease-free koalas. The animals are listed as vulnerable across New South Wales.Koalas could be extinct in New South Wales within 30 years. That grim warning came from a parliamentary committee in June.The state government said it is determined to save one of Australia’s most recognizable indigenous animals. It is creating a new reserve on Sydney’s suburban fringe to allow koalas to use protected woodland corridors to travel between habitats. One hundred thousand trees also will be planted.“We are here to announce the Georges River Koala National Park,” said Matt Kean, environment minister for New South Wales. “We will be securing 1,885 hectares of koala habitat to ensure that the koala survives in this fortress population forever.”A plan to build hundreds of homes in the area could be vetoed by the state government after scientists found that koalas wouldn’t be properly protected.Kean warned the construction company he may not approve the development plans.“I will not be signing off on the bio-diversity certificate unless your development meets all the recommendations of the chief scientist,” he said.The developer has said that protecting native wildlife was a key consideration, but it has yet to formally respond to the state government.Critics have said the koala sanctuary is not big enough. But Cate Faehrmann, a Greens parliamentarian, believes it is a good start.“It is a welcome first step,” Faehrmann said. “Thank you very much, New South Wales government, for recognizing that this koala colony out in Campbelltown — it is our only chlamydia-free population. It is so important. There is anywhere between 200 and 600 koalas out there that have to be protected. They have recognized this.”Koalas face many threats, including chlamydia – a bacterium that can cause pneumonia and infertility. Bushfires, habitat loss, attacks by dogs and road accidents are also significant threats. But in other parts of southern Australia, officials have said there are too many koalas, and that ‘overabundant’ populations have damaged valuable trees.Also, south of Sydney, a group of koalas rescued from last summer’s devastating bushfires has been released back into the wild. Three of the animals are named after the crew of a U.S. water-bombing aircraft that crashed in Australia in January.