Koalas will soon have protection from a deadly sexually transmitted disease that has devastated wild populations, following the approval of a nationwide chlamydia vaccine rollout.

The Australian Pesticides and Veterinary Medicines Authority has approved the single-dose vaccine, developed by the University of the Sunshine Coast (UniSC) after more than a decade of research.

The approval means the treatment can now be distributed nationally to protect one of the country's most vulnerable species, and is no longer limited to trial conditions.

UniSC and the Queensland University of Technology (QUT) have each developed separate vaccines, but the Sunshine Coast is the first to win approval.

The QUT trial vaccination requires two doses, while the UniSC vaccine works with one.

Vaccine needed urgently

Chlamydia is one of the leading threats to koalas, causing painful urinary tract infections, infertility, blindness and death.

UniSC professor of microbiology Peter Timms said the single-dose version made the vaccine practical for use in the wild.

"That's very important because with a koala, you're not going to get a chance to capture it twice."

Koala populations in Queensland, New South Wales and the Australian Capital Territory were listed as endangered in 2022.

South-east Queensland's wild koala population has dropped to fewer than 16,000.

Professor Timms said vehicle strikes, animal attacks and the ongoing loss of habitat due to urban development also threatened the species.

He said the new vaccine was urgently needed.

"There are less koalas today than there was yesterday," Professor Timms said.