More than 130 fires broke out across a parched New South Wales while, in Victoria, fire tore through grassland near Chepstowe, 34 kilometres west of Ballarat. The Chepstowe blaze injured a firefighter, destroyed at least two homes, and closed major roads.

The fire, which began late on Tuesday, came as hundreds of bushfires burned across the nation, bringing large parts of regional Australia to a halt as temperatures soared.

Another large bushfire at Kentbruck in the state's south-west also continued to burn out of control, already razing 9000 hectares, and westerly winds forced the fire back on itself.

The Chepstowe fire destroyed several properties. Ambulance Victoria was called in to treat a firefighter whose hands were badly burned. Traumatised residents said they feared they had lost everything after the fire ripped through, and brought out two firefighting helicopters, as well as 57 Country Fire Authority units.

More than 130 fires were burning in New South Wales on Tuesday afternoon, threatening homes and injuring firefighters as regional communities in the state bore the brunt of the ''catastrophic'' conditions emergency services had warned of.

Power to almost 10,000 homes in Sydney, the central coast and the Southern Highlands was also cut for a time, because of widespread equipment failures.

And one of the NSW blazes temporarily cut the Hume Highway, almost halfway between Melbourne and Sydney.

As night fell, the worst fires continued to burn in southern parts of the state, around Bega, Cooma, Wagga Wagga and Nowra in the Shoalhaven region.

Incredibly, by 8pm on Tuesday night, despite 55,709 hectares being razed across the state, there were no reports of loss of life and the only building destroyed a hay shed.

Rural Fire Service Commissioner Shane Fitzsimmons praised the ''extraordinary'' firefighting effort that was still taking place in New South Wales, in ''dirty, hot difficult conditions''. ''We have been very fortunate,'' he said.

Close to 1500 firefighters were battling blazes with thousands more volunteers on standby as temperatures soared on Tuesday, fanned by winds of more than 70 km/h in some areas.

Opposition Leader Tony Abbott was among those waiting to help if a fire broke out in bushland on Sydney's north, joining his local fire brigade where he volunteers.

At 5pm, the biggest threat was at Deans Gap, in NSW's Shoalhaven region, where fires were fuelled by strong, hot wind gusts.

Meanwhile a fire in the town of Tarcutta, near Wagga Wagga, burned through hundreds of hectares of land, isolated residents in properties to the north-west of town, along Mates Gully Road.

They were warned to stay and protect themselves from radiant heat as it was too late to leave.

Police in western Sydney also arrested three juveniles over what they believed was a deliberately lit fire in Shalvey, in the west. Up to 15 fire crews and five police cars battled for two-and-a-half hours to bring the blaze under control, with 10 hectares affected.

All NSW national parks, reserves and state forests were closed to the public due to the fire risk, while the total fire ban has been extended into Wednesday.

A man was charged for breaching the total fire ban in NSW's Illawarra region after he allegedly lit a cooking fire, and allegedly tried to prevent police from extinguishing it as hot ash fell to the ground. The 70-year-old property owner is due to appear at Port Kembla Local Court on April 4.

Of the fires burning in NSW, several were thought to be deliberately lit, including a grass fire in Shalvey in western Sydney.

With CHRISTOPHER KNAUS, LISA COX