A bushfire south of Perth has been contained but remains uncontrolled.

Some 100 firefighters battled the 6000-hectare blaze on Saturday before it started to slow its spread.

Aerial support was also dispatched to the Donnybrook-Balingup Shire on Saturday.

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

An emergency warning remained in place for the fire area, with residents told to flee.

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

By Finbar O’Mallon in Sydney