Dozens of out-of-control fires have burnt vast tracts of Australia, destroying homes and crops and killing animals, but not a single person has died.

The success of the operation to safeguard lives has much to do with a detailed guide to surviving bush blazes, along with an official danger rating system that was introduced after 173 people perished in the 2009 Black Saturday firestorm.

In addition the Rural Fire Service (RFS) is extremely proactive in promoting safety precautions and warns every family how to make their own survival plans.

RFS Deputy commissioner for New South Wales Rob Rogers spent Friday morning on radio and television bracing the nation for more to come as firefighters faced soaring temperatures in the battle to douse more than 100 fires.

"We've obviously got severe fire danger," Rogers said running through the basic requirements of survival designed to "protect the lives of your family".

"Prepare, act, survive," say the guidelines, continuing: "The majority of deaths during bushfires result from people trying to leave their homes at the last moment."

The danger ratings system culminates in severe, extreme and catastrophic conditions, which are used to determine whether to evacuate or to stay and fight.

A severe warning was declared in parts of Victoria state on Friday with a heatwave expected to intensify at the weekend.

Catastrophic ratings were in force in some areas last Tuesday -- officially billed as the worst fire day in New South Wales history -- but no one died.

Anyone doubting the risks, however, is advised in the RFS Bushfire Survival Plan that: "A bushfire can be a terrifying situation. Strong gusty winds, intense heat and flames will make you tired quickly.

"The roaring sound of the fire approaching will deafen you. Embers will rain down, causing spot fires all around you.

"Power and water may be cut off. You may be isolated. It will be dark, noisy and extremely physically and mentally demanding.

"If you have any doubts about your ability to cope, you should plan to leave early."

Despite the severity of the warnings plenty of people decide to stay and defend their homes. And the guidelines, while noting that everyone must flee in the face of a catastrophic rating, tells them how to do it.

An emergency survival kit, protective clothing and a well-prepared home are integral to any plan.

The exhaustive kit includes a portable battery-operated radio, waterproof torch, spare batteries, candles with waterproof matches, first aid kit, pocket knife, important documents and at least three litres of water per person per day.

Loose fitting clothing made from natural fibres, heavy cotton drill or denim is advised. Synthetic fabrics such as nylon can easily melt or burn.

Other items include a wide brimmed or hard hat to "stop embers from dropping onto your head or down the back of your shirt", goggles, gloves, a mask or cloth to cover nose and mouth and sturdy leather work boots.

Preparations to defend a home, regardless of whether occupants choose to fight or flee, are also serious, with Neighbourhood Safer Places designated as a last resort when the flames rise.

"A well prepared home is easier to defend and more likely to survive. It also gives you more protection if you have to take shelter," says the official bushfire plan.

The advice includes planting trees and shrubs with low oil content that are less likely to ignite, cutting overhanging vegetation, replacing damaged roof tiles, building non-combustible fences, and keeping grass short.

Hoses should be long enough to reach everywhere, flammable items must be stored away from the house, metal flywire or solid screens should be installed on outside windows and doors, and doormats should be non-combustible.

Despite fires raging across southeast Australia, few homes have been destroyed, although thousands of head of stock have died and more than 350,000 hectares (865,000 acres) of land has been scorched.