Firefighters in New South Wales and Victoria are making the most of milder conditions and welcome rains to head off a possible “mega-blaze” developing in the coming days.

Dangerous fire weather is set to return to Australia’s south east on Friday, with temperatures expected to reach the mid-30s on the coast and low-to-mid-40s inland.

The race to prepare for the rise in temperature comes as the NSW Rural Fire Service confirmed at 5pm Tuesday that two men missing on NSW’s fire-ravaged far south coast had been confirmed safe.

Earlier police sent in heavy machinery to clear the road to Kiah, south of Eden, where one of the missing men lived.

The other, a 70-year-old from Lower Towamba, west of Eden, had not been seen for several days.

The death toll remains at 20, with emergency services adding the November 9 death of Chris Savva to the count.

RFS Commissioner Shane Fitzsimmons, meanwhile, warned there was “every likelihood” the Corryong fire in Victoria’s north-east will merge across the border with fires in southern New South Wales in the coming days.

Victorian Country Fire Authority State Response Controller Gavin Freeman said firefighters were monitoring the area closely.

Mr Freeman told Channel Nine’s Today that the two fire systems could join, creating a blaze that was almost half a million hectares in size.

Fire authorities fear high temperatures and strong winds could merge three fires across New South Wales and Victoria into one 'mega blaze'. #9Today pic.twitter.com/J1TDoC23pW

— The Today Show (@TheTodayShow) January 5, 2020

Victorian Emergency Services Commissioner, Andrew Crisp, said while there’s “every chance” a ‘mega-blaze’ could form, that did not necessarily increase the danger.

“It is mega in terms of area. Just because you’ve got a large area, it doesn’t mean it’s all fire,” Mr Crisp told reporters Monday.

Brief respite

Some 2500 personnel are working across Victoria’s fire grounds – attempting strategic back-burns to contain fires, strengthening containment lines and working to bring some fires under control.

But there are concerns that the rains bringing relief to the firefighting effort is not falling in great enough quantities to extinguish the blazes, and could in fact hinder some of the work.

Bushfire behaviour expert Thomas Duff told the ABC a small amount of rain could be a nuisance because it results in patchy fires within the control lines.

“Having unburnt areas within your control lines is actually quite dangerous because they can be a source of new fires or spot fires when things dry out again,” Dr Duff said.

Mr Andrews warned against complacency ahead of Thursday and Friday’s worsening weather.

“Messages will be sent out Thursday and Friday this week. They are about life and death, and people need to remain vigilant,” he said.

“This is not over by a long shot.”

Crews preparing for more bad fire conditions:

Mounting insurance bill

Warnings of a ‘mega-blaze’ come as the RFS confirmed Tuesday that 2241 homes had been destroyed or damaged in the state so far this fire season, with 1588 of them left uninhabitable.

In Victoria, Premier Daniel Andrews said at least 200 homes had been destroyed, while the South Australian Government said 56 homes were destroyed in the Kangaroo Island fires.

Those figures are expected to rise as authorities gain access to more fire affected areas.

The Insurance Council of Australia says the estimated damage bill has doubled in two days to $700 million.

Campbell Fuller from the council said there were almost 9000 insurance claims for fire-related damage and destruction since the bushfires began in September.

About 20 per cent of the claims have been assessed, with half of those already settled.

Insurance industry bosses met with Treasurer Josh Frydenberg in Canberra on Tuesday.

Mr Frydenberg said insurers were already getting builders lined up but the government wanted them to focus on using local tradesmen.

“These communities need to rebuild and the more jobs that can be provided locally the better,” he said.

Firefighter farewelled

Firefighters formed a guard of honour to farewell RFS volunteer Andrew O’Dwyer, who died last month when his fire truck rolled while battling the large Green Wattle Creek blaze near the town of Buxton.

Mr O’Dwyer lost his life in December. Photo: RFS

Mr O’Dwyer, 36, was remembered as a proud RFS member whose greatest achievement was his young daughter.

A requiem mass was held at Our Lady of Victories in the Sydney suburb of Horsley Park, attended by hundreds of family, friends and RFS members.

Today we celebrate the life of firefighter Andrew O’Dwyer of the Horsley Park Rural Fire Brigade. Andrew was tragically killed along with fellow member Geoff Keaton on December 19 while fighting the Green Wattle Fire near Buxton. #NSWRFS pic.twitter.com/vFTSJwdmPA

— NSW RFS (@NSWRFS) January 7, 2020

Prime Minister Scott Morrison, NSW Premier Gladys Berejiklian, state Emergency Services Minister David Elliott and federal Labor MP Chris Bowen were also among the mourners.