THE hellish inferno that engulfed Victoria and wrought indescribable suffering on the weekend has claimed hundreds of lives, with no end to the official death toll in sight.

The worst natural disaster in Australia's history has destroyed entire communities, flattened at least 750 homes, left up to 5000 people homeless, burnt through more than 330,000ha, killed thousands of stock and destroyed thousands of hectares of pasture.

For sheer loss of life, the fires completely overshadow the destruction caused by the country's previous worst fires - those of Black Friday and Ash Wednesday.

As Premier John Brumby ordered a Royal Commission into every aspect of the disaster, several communities, including Healesville, Yarra Glen and Toolangi, were still fighting for survival yesterday as the fires continued to rage.

The death toll in the areas where the fires have already destroyed everything in their path has been growing by the hour, as emergency services workers continue to find corpses in burnt-out houses and cars.

On Saturday night, fire virtually obliterated Marysville, killing at least 12 people and sparing just a handful of homes.

At least 39 people have died in Kinglake and Kinglake West while scores of others have been killed in dozens of communities including Narbethong, Steels Creek, Callignee, Strathewen, St Andrews, Humevale and Wandong.

Victoria Police Commissioner Christine Nixon yesterday said a special police taskforce - Operation Phoenix - would conduct the biggest investigation of its kind in the nation's history to track down the arsonists thought responsible for many of the fires.

Prime Minister Kevin Rudd branded the arsonists mass murderers.

As rural Victorians began to confront the inconsolable grief from the death of friends and families and the destruction of their communities, debate raged over whether a lack of fuel reduction burning was a key factor in the tragedy.

Bushfire scientist David Packham said successive governments had refused to pay heed to the evidence linking high fuel loads with catastrophic fires.

"Every objective analysis shows that unless the fuels are maintained at near the levels that indigenous people achieved, then we will have unhealthy and unsafe forests that will generate disasters like last Saturday," Dr Packham said.

The head of CSIRO's bushfire research unit, Phil Cheney, called for the Royal Commission to examine fuel-reduction burning in Victoria.

Victorian Farmers Federation president Simon Ramsay said governments had to reassess their policies on native vegetation and residential development in heavily forested areas.

The fires - which killed scores of people trying to flee their homes at the last minute - also sparked calls for an end to Victoria's "stay and defend" policy, whereby property owners are advised to stay at home to protect it or leave early.

But CFA chief fire officer Russell Rees said the policy was based on sound evidence.

"It is the application of that policy and a lack of an alternative that we need to work on," Mr Rees said.

"People need to understand that a late departure is the most deadly."

As the full impact of the fires became apparent, farmers around Australia immediately swung into action to help fire-ravaged Victorians.

Thousands of tonnes of fodder have already been collected and are on their way to the most affected areas.

VFF president Simon Ramsay said some of the parts of Australia sending the fodder were as drought affected as Victoria.

"It feels pretty good to see the real spirit of comradeship from farmers everywhere, as well as communities around Melbourne; how local communities support each other," Mr Ramsay said.

"Most of farmers donating feed are also CFA volunteers and, all at their own cost, they're using their machinery, their time, to keep helping others."