That is, unless the government makes drastic changes to knocking down trees.

An estimated 64,000 koalas were killed when 5.5 million hectares was destroyed during the 2019-20 Black Summer bushfires in NSW.

Ahead of state elections next year, scientists, politicians and conservationists gathered to lobby both major parties to keep koalas from vanishing if they are voted into power.

The former federal government listed the species as endangered in February just before unprecedented floods inundated northern NSW.

A 2020 NSW parliamentary report found koalas would become extinct by 2050 in the state unless government intervention to prevent habitat loss was mandated.

Meanwhile, persistent rain may cause more flash flooding across Victoria over the long weekend as the state braces for possibly its coldest Melbourne Cup Day in nearly three decades.

More than 500 calls for assistance were made to Victoria's State Emergency Service on Friday and authorities have urged residents to remain alert with heavy rain and storms set to soak parts of the state.

Western Victoria will be pummelled by heavy rain on Sunday afternoon, with damaging northerly winds expected across southern and elevated areas.

In other news, a group of women and children linked to Islamic State and stranded in displaced person camps in north eastern Syria have arrived in Australia.

The four Australian women, who had been in the al-Roj camp since the fall of the militant terrorist group, and 13 children landed in Sydney on Saturday after being taken to Erbil in Iraq to begin their journey.

Earlier this month, the Albanese government confirmed a rescue plan to bring home 16 women and 42 children who are families of IS members.

The first people removed were assessed as the most vulnerable of those being held.

Meanwhile, radiologists have probed changes to the brains of astronauts that could have significant implications for the future of human colonisation on the moon and Mars.

The annual gathering of the Royal Australian and New Zealand College of Radiologists in Adelaide will hear of world-first data from MRIs taken on astronauts from NASA, the European Space Agency and the Russian Space Agency.

They reveal significant changes in the brain associated with long exposure to microgravity, including Spaceflight Neuro-Ocular Syndrome.

The syndrome can have a significant impact on those in space for long periods with symptoms including vision issues, changes to the brain's structure and a shift in brain fluid.

THE NEWS YOU NEED TO KNOW: