Cooler temperatures and easing winds Monday helped firefighters contain a bushfire that killed two people and razed 143 properties, with clean-up efforts getting underway.

The inferno, sparked by lightning six days ago, burnt through 71,000 hectares (175,000 acres) in Western Australia state, leaving a trail of destruction, the latest in a series of summer blazes that have so far left eight people dead.

"The weather conditions are great today and they were in the last 24 hours so we have been able to essentially contain this fire," Western Australia's Emergency Services Minister Joe Francis told national radio.

"It's not totally under control yet but we are very optimistic about the next 24 hours as well."

Alert levels have been downgraded from emergency to watch and act for towns in the area including Waroona, Hamel and Yarloop, a historic mill community some 110 kilometres (70 miles) south of Perth where two bodies were found in the blackened ruins of burnt-out houses.

The fire, one of the worst to hit the region in recent years, destroyed 143 properties, including 128 homes in Yarloop which was virtually flattened, the state's Department of Fire and Emergency Services (DFES) said.

Western Australia's state premier Colin Barnett has declared a natural disaster, giving residents access to greater financial support, with the Insurance Council of Australia estimating losses of at least Aus$60 million (US$42 million).

Francis said he was "exceptionally proud" of the efforts of hundreds of firefighters, many of them volunteers.

"They put themselves through significant danger to get through some exceptionally difficult fires to save people's lives," he said.

Bushfires are common in Australia's hotter months, with four deaths in Western Australia in November. Another two people perished in neighbouring South Australia state in the same month.

DFES commissioner Wayne Gregson warned on Sunday that the worst of the bushfire season was yet to come.

"There is still another 10 or more weeks to go in what is predicted to be a difficult bushfire season," he said.

Australia's worst firestorm in recent years devastated parts of the southern state of Victoria in 2009, destroying thousands of homes and killing 173 people.

Two dead as firefighters battle huge Australia bushfire
Perth, Australia (AFP) Jan 10, 2016 - Two people have died and more than a hundred homes have been destroyed in a huge bushfire, Australian authorities said Sunday, as firefighters battled to tame the out-of-control blaze.

The inferno -- which has razed about 71,000 hectares (175,000 acres) in Western Australia state -- is the most recent in a series of bushfires that have kicked off a hot summer season, with the latest deaths lifting the national toll to eight.

The two bodies were found in burnt-out houses in Yarloop, a historic mill town some 110 kilometres (70 miles) south of Perth that has been devastated by the bushfire -- one of the worst to hit the region in recent years.

The bodies are believed to be those of two missing men aged 73 and 77, Western Australia Police told AFP.

"It's just another day of catastrophe, isn't it?" Tania Jackson, the head of the regional council, told the Australian Broadcasting Corporation after news of the men's deaths.

"Each day that has gone by seems to bring worse news. It's devastating."

The bushfire -- which is entering its fifth day after reportedly being started by a lightning strike -- has destroyed 143 properties, including 128 homes in Yarloop, the state's Department of Fire and Emergency Services (DFES) told AFP.

Some 250 firefighters are fighting the blaze, which has a perimeter of about 226 kilometres, and authorities said Sunday afternoon that it was "contained" within the fire zone, but not yet under control, amid cooler weather on Sunday.

"Overnight and today, favourable conditions came in and it's a lot cooler here today and that has allowed firefighters to gain more ground on the fire and to increase containment lines," a DFES spokeswoman told AFP.

DFES said several towns in the region remained under threat.

"Unless you are ready and prepared to actively defend your property, evacuate to the south via the South Western Highway if safe to do so," it said in an emergency warning.

- 'Difficult bushfire season' -

Western Australia's state premier Colin Barnett said the event had been declared a natural disaster, a measure that gives residents access to greater financial support, adding that the "damage bill is going to be very significant".

Yarloop residents spoke of how the bushfire tore through their town in just seven minutes, as aerial footage showed blackened ground, burnt-out shells of vehicles and houses reduced to brick fireplaces.

"During the day, the hills were very dark and smoking," dairy farmer Joe Angi told the ABC on Saturday.

"But the wind picked up just on dark and she's just come down from the hills, straight down, flat out. It was tumbling over itself like a wave of fire."

Bushfires are common in Australia's hotter months, with four deaths in Western Australia in November. Another two people perished in neighbouring South Australia state in the same month.

DFES commissioner Wayne Gregson warned that the worst of the bushfire season was yet to come.

"There is still another 10 or more weeks to go in what is predicted to be a difficult bushfire season," Gregson told Perth's Sunday Times newspaper.

"Late January to early February is traditionally the most intense summer period, when we can experience hot weather with dry winds and seasonal lightning."

Australia's worst firestorm in recent years devastated parts of the southern state of Victoria in 2009, destroying thousands of homes and killing 173 people.