Firefighters raced to contain a major blaze on Monday before the return of strong winds and a heatwave, following the loss of 26 homes in the worst brushfire conditions in South Australia in 30 years.

The state fire service said properties were still at risk after nearly 12,500 hectares of scrub and farmland were razed in the Mount Lofty Ranges, east of Adelaide, at the weekend.

South Australia state Premier Jay Weatherill said that with cooler weather and calmer winds, it was now a race against time before dangerous conditions develop on Wednesday in the Adelaide Hills.

'Clear danger'

"There is still clear danger," he told reporters, as water bombing aircraft dropped hundreds of thousands of liters of fire retardant on the blaze, which has a 238-kilometer perimeter.

"This is by no means over," Weatherill said.

"We're really racing against time to try to make sure that we get as much of this contained before the hotter weather and the stronger winds expected later in the week."

He confirmed the loss of 26 homes and 41 outbuildings. The latest figures were reported after checks on just 20 of 59 affected areas.

At least 29 people, mostly firefighters, have suffered minor injuries.

In Kersbrook, one of the worst hit villages in the Adelaide Hills, resident Dave Miller surveyed the scene of destruction where his home once stood.

The 60-year-old told The Associated Press that he had very little left. "No house, not very much of anything, mate."

"I've got a tank still standing with 4,000 liters of diesel in it, but I've got nothing else," he said.

Like most residents, Miller vowed to rebuild and has no intention of leaving, despite the annual wildfire menace.

"I'll stay up here. I'll get a caravan or something to live in and just keep going."

Temperatures were forecast to soar again above 38 C on Wednesday, after highs of well over 40 C at the weekend in the Adelaide Hills, which has a population of 40,000 and is dotted with scenic villages known for their farms and wineries.

Winds crucial

Country Fire Service Chief Officer Greg Nettleton said the winds would be crucial to the next stage of the operation.

"At the moment I think they're predicting about 35 km/h. That's enough, given the dryness of the country, for the fire to spread. So our number one priority is to secure the outer perimeter of that large fire so it doesn't impact on further communities," Nettleton said.

The prospect of heavy rain on Friday was encouraging. Bureau of Meteorology spokesman Neil Bennett said Adelaide could receive up to 50 millimeters of rain if a tropical low spreads from western Australia as currently predicted.

AFP - AP