By Kat Wong and Callum Godde 

Humans and animals alike have been warned to take caution as the risk of heat-related harm rises with record-breaking temperatures.

A spring heatwave has cranked up the mercury, with Queensland and NSW both hitting their highest recorded temperatures for October.

Birdsville in Queensland’s southwest reached 46.1C while Bourke in far north NSW reached 44.8C on Tuesday.

Parts of Sydney were expected to flirt with maximums of 40C on Wednesday, according to weather bureau senior meteorologist Angus Hines.

The temperature had climbed to nearly 37C in the city centre by early afternoon, while western and southwestern suburbs had readings above 38C.

Walgett, in northwest NSW, had a temperature of 39.1C.

“These are typically temperatures that we would only see in a summer heatwave, but it’s still spring,” Mr Hines said.

Victorians were meanwhile told to brace for destructive winds and a risk of thunderstorm asthma conditions.

NSW Health Minister Ryan Park urged people to seek shade, avoid the outdoors and drink water regularly.

“We’re asking everyone today to take steps to protect themselves,” he said.

“Let’s also look out for another – our older friends and family, babies and young children and pregnant women.”

Total fire bans have been declared for multiple areas including the Sydney, Hunter and Illawarra regions, and parts of northwest NSW.

Nine bushfires were burning out of control across the state in the morning.

The hot and windy conditions could also put animals in harm’s way, International Fund for Animal Welfare officer Robert Leach said.

“Animals don’t have fire plans. We do,” he said.

“We are trying to do better for our wildlife, so they do not suffer so immensely again.

“Animals like koalas are only just recovering after the devastation of Black Summer, we cannot afford another catastrophe.”

NSW authorities warned walking tracks and remote campgrounds in national parks across the areas could be closed “at short notice” if conditions worsened on Wednesday.

Relief from the heat is expected to arrive across southern Australia on Wednesday night.

But those in the north won’t be so lucky, with temperatures tipped to remain high on Friday and into the weekend.

Maximums were forecast to reach 35C in Darwin in Wednesday, ahead of Canberra (31C), Brisbane (30C) and Melbourne (23C).

Victorian Emergency Management commissioner Tim Wiebusch said damaging winds were forecast to hit the state’s west in the morning and reach the state’s east in the afternoon.

“We’re asking Victorians to ensure that they are prepared for power outages,” he said.

“That means be aware of fallen powerlines that may be on the ground but also ensure that you’ve charged your mobile devices.”

The Bureau of Meteorology has warned gusts between 90km/h to 110km/h are expected to be “widespread” and could rise to 120km/h for the southwest Victorian coast, Bellarine and Mornington peninsulas and Bass coast.

Trees or branches were “very likely” to come down in the wild weather, creating hazards on the roads and properties, Geb Abbott from Victoria State Emergency Service said.

She called for drivers to consider alternate routes before hitting the road or if they needed to travel at all.