SYDNEY, Dec. 20 (CGTN) -- Two volunteer Australian firefighters died while battling blazes around Sydney, authorities said on Friday, forcing Prime Minister Scott Morrison to cut short a vacation in Hawaii as temperatures were again set to soar.

Australia has been fighting wildfires across much of its east coast for weeks, leaving eight people dead, more than 700 homes destroyed and nearly three million acres (1.2 million hectares) of bushland burnt.

"There is no finer person available in my view than someone who is willing to put themselves on the line for the want of nothing in return, no remuneration, nothing other than to make a positive difference in their local community," New South Wales (NSW) Rural Fire Service Commissioner Shane Fitzsimmons said.

"There is a definition of hero and these two line up to it."

Fitzsimmons named the dead firefighters as Andrew O'Dwyer, 36, and Geoffrey Keaton, 32. Both men were fathers to 19-month-old children, Fitzsimmons said.

Earlier three other firefighters were engulfed by flames as fierce winds fueled bushfires across the same state. Two men were airlifted to hospital with burns to their faces, arms and legs, while a female colleague was taken by ambulance to hospital.

Now, the injured firefighters are said to be in stable condition.

Bushfires are common in Australia's hot, dry summers, but the ferocity and early arrival of the fires last month in the southern hemisphere spring is unprecedented.

The crisis has stoked widespread public anger, with protests around Australia, and irritation fueled this week by Morrison going on leave. He has weathered a storm of criticism on social media, adding to criticism that his government is failing to deliver adequate climate change policies.

Just hours after confirmation of the deaths of the firefighters, Morrison said he would be returning and issued an apology. "I deeply regret any offense caused to any of the many Australians affected by the terrible bushfires by my taking leave with family at this time." On Thursday, Australia recorded its hottest day on record as national temperatures topped more than 42 degree Celsius (107.6 degree Fahrenheit).

The fires have resulted in days of heavy pollution in the city usually known for its sparkling harbor and blue skies.