Cool change expected to assist firefighters in containing disaster More than 30 homes are feared destroyed as firefighters battle the worst bush fire in South Australia for three decades, with officials warning on Sunday of a threat to live seven as weather conditions improve.

The state's Country Fire Service said the intense fire, which broke out on Friday in the Mount Lofty Ranges east of Adelaide, was continuing to burn in all directions at Sampson Flat, threatening lives.

But a cool change on Sunday was expected to help them work to contain the fire ahead of a forecast rise in temperatures again on Wednesday.

"I can confirm that 12 homes have been destroyed and it's feared that a further 20 homes have also been lost," South Australian Premier Jay Weather ill said.

"However, the conditions for fire fighting have improved. The weather is cooler and the weather conditions will permit aerial fire fighting.

"This is important because it is fore casted that we will have worsening weather conditions on Wednesday so it's critical that we make head way on reducing the active edges of this fire front."

Large area razed

Weather ill said following a visit to the site of the bush fire on Sunday afternoon that he had seen "many burnt-out houses" and also "fires licking at the edges of a number of houses".

"There is a lot of hard work to be done. The conditions out there are difficult and in some respects dangerous," he added.

More than 11,000 hectares have been burned in the Adelaide Hills, an area in the Mount Lofty Ranges with a population of about 40,000 and that is dotted with scenic villages and known for its farming produce and wineries.

"Alarge number" of dogs and all cats died when the blaze tore through a pet boarding property in the area, the owners of Tea Tree Gully Boarding Kennels&Cattery said.

But they added that while some 30 dogs were lost, more than 40 others were rescued from the blaze.

Temperatures are forecast to soar to 39 C on Wednesday, but the winds are not expected to be as strong as they have been over the past two days.

Hundreds of firefighters from the neigh boring states of Victoria and New South Wales joined their South Australian counterparts on Sunday, taking the total crew battling the blaze to more than 800.

Bush fires are common in the country in summer between December and February.

"Black Saturday", the worst firestorm in recent years, devastated southern Victoria in 2009 as it razed thousands of homes and killed 173 people.