A bushfire south of Perth has been contained but remains uncontrolled, with emergency officials calling for public vigilance amid changing conditions.

Emergency officials have warned there is a possible threat to lives and homes in the area and have advised residents to flee.

One home has already been destroyed and three others damaged, the ABC reports, further confirming two people sustained injuries while defending their properties.

The watch-and-act alert was issued after some 100 firefighters battled the 6000-hectare blaze in the Donnybrook-Balingup Shire on Saturday before it started to slow its spread.

The fire, believed to have been sparked by lightning, was moving slowly northwest as of Sunday morning after breaching containment lines on Saturday.

Adelaide Hills blaze

Meanwhile, in South Australia, firefighters have managed to contain a bushfire in the Adelaide Hills, just east of the state capital.

Residents in Montacute had earlier been told to leave or take shelter on Saturday.

But by that night the fire was contained with firefighters remaining on scene to monitor hotspots.

Firefighters had been battling the blaze over steep, inaccessible terrain in the Adelaide Hills with 15 tankers and eight aircraft involved in extinguishing it.

-with AAP