NSW firefighters are “giving their all” to contain large and complex bushfires before conditions worsen amid forecast high temperatures and dry winds.

After a devastating end to last week – when two firefighters were killed and as many as 100 houses were destroyed in the state – firefighters have taken advantage of milder conditions to strengthen containment lines.

Almost 1,300 firefighters were in the field on Friday morning as 70 bush and grass blazes continued to burn, with 33 of them uncontained.

NSW Rural Fire Service Commissioner Shane Fitzsimmons said firefighters had been doing “really difficult ... challenging work” in areas like the Blue Mountains and South Coast.

They had been establishing containment and control lines with hand tools and machinery, along with extensive backburning, Fitzsimmons told Seven’s Sunrise on Friday.

“Because these fires are large, they’re complex and they’re very prone to the elements, once these weather conditions turn around, we know we’re going to see increased fire activity,” he said.

“So they’re just giving their all to shore up protection and trying to consolidate and contain them as much as they can.”

Meanwhile, NSW Emergency Services Minister David Elliott is going on a family holiday overseas, with Counter Terrorism and Corrections Minister Anthony Roberts acting in the role from Friday.

Elliott, who postponed the break once previously and has recently lost family members, said he would continue to receive two briefings each day from the RFS commissioner and stay in contact with his office and other authorities.

“If the bushfire situation should demand it, I will return home without hesitation,” he said in a statement.

Earlier in December Prime Minister Scott Morrison was widely criticised for going on holiday in Hawaii when raging bushfires threatened lives and homes in Australia.

Fitzsimmons told ABC News on Friday Elliot’s leave would not stop work on the firefighting effort.

“I’ll be maintaining contact with Minister Elliott while he’s away, and I’ll be maintaining a very close relationship with the acting minister,” he said.

The Bureau of Meteorology expects the fire danger to worsen into the new week with increasing heat and winds.

Temperatures on Tuesday are forecast to reach maximums of 43C in Penrith, 35C in Katoomba, 40C in Picton, 36C in Griffith and 40C in Mudgee.

Fitzsimmons said they were not expecting previous catastrophic conditions to return, but firefighters and communities would be challenged at the end of this week and early into next week.

“It’s certainly going to be another tough period with temperatures up into the 40s, very dry air, very low humidities and the winds turning back around from the west and the northwest,” he told the ABC.

Very high fire danger is forecast for nine NSW regions on Friday including the ACT, Greater Hunter and central and southern ranges.

Highs of 36C are expected in Canberra, while regional centres such as Mudgee, Goulburn, Tamworth, Dubbo and Griffith are set for days above 35C.

The federal government, meanwhile, has extended the Australian disaster recovery payment to the mid-western local government area of NSW, enabling payments of $1,000 per adult and $400 per child to those worst hit by bushfires.

A statewide code red was declared in South Australia on Friday to provide extra help for homeless people as temperatures soar.

Adelaide was forecast to reach 40C on Friday with the mercury tipped to stay at least in the high 30s until Monday.

Human Services Minister Michelle Lensink said increasing services to the homeless was vital in the extreme heat.

“Keeping vulnerable South Australians safe and well in the extreme heat forecast over the next few days is our priority,” she said.

“During a code red, agencies across Adelaide will extend their daytime operating hours to ensure people sleeping rough are keeping cool and well-hydrated during the extreme heat.”

SA’s looming heatwave is the second so far in December after last week’s run of four days with temperatures in the mid-to-high 40s.

On Friday the hottest spots were expected to be in the state’s north with 45C maximums forecast for Oodnadatta, Oak Valley and Tarcoola.

The heatwave will reach Victoria on Friday bringing temperatures over 40C across the whole state during the weekend.

As the weather starts heating up before it drops again on New Year’s Eve, emergency services have urged Victorians to be extremely aware of weather conditions.

Statewide heat alerts will be in place on Saturday and Sunday. Melbourne is forecast to reach 43C in some suburbs on Monday.

New fires have also been deemed as likely to start as a result of dry lightning, particularly in the east of the state.

Authorities urged people to be aware of potentially dangerous fire conditions, particularly in East Gippsland.

Plans to walk, hike, cycle or or drive in remote parks and forests were discouraged, as new fires can quickly threaten lives.

Significant fires burning may impact communities from the Great Dividing Range to the coast between Bairnsdale and Marlo.

The fires in East Gippsland have been burning since 21 November, burning more than 100,000 hectares while travelling more than 1,000km.

Smoke from fires burning in Gippsland and NSW is currently affecting air quality in the north-east of Victoria.