Authorities are urging holiday travelers to stay informed about increasing fire risks across several states as conditions worsen.

Extreme weather is expected on December 26, with temperatures potentially reaching 40°C and strong, dry winds, which could exacerbate fire spread.

In Adelaide, temperatures are forecasted to hit 36°C on December 26, following a scorching 37°C on Christmas Day.

In South Australia, firefighters have advised residents in the Onkaparinga Hills to evacuate due to an out-of-control bushfire, although warnings have since been downgraded as conditions are monitored.

A bushfire alert in Western Australia has escalated, warning residents near Northam that it is 'too late to leave' as conditions deteriorate.

In New South Wales, while several small bush and grass fires are under control, high fire dangers are anticipated shortly after Christmas.

To bolster firefighting efforts, approximately 100 personnel from New South Wales, ACT, Queensland, and Tasmania are being deployed to Victoria.

Residents near bushfires in Victoria's west have been granted a two-hour window to return home to collect belongings before Christmas.

In areas affected by a significant 41,000-hectare bushfire that has been burning for a week, residents must provide proof of residence to access their homes.

In response to the crisis, Country Fire Authority chief officer Jason Heffernan announced 'Operation Yuletide' to help residents retrieve Christmas items and presents.

Heffernan noted that cooler conditions on December 23 aided firefighters in containing the southern Grampians fire, although challenges remain.

In addition to the Grampians fire, another blaze near Bullengarook has been contained, while a fire at the Gurdies in Gippsland continues to burn.