Fires burning in the shires of Gingin and Dandaragan have been a constant threat to lives and homes for more than three days.
200 firefighters and more than a dozen aircraft strengthened containment lines as they waited for strong easterly winds to kick in.
The wind is expected to push the fire towards the coast where popular holiday spots are in the firing lines.
Wedge Island is one of those areas which has firefighters most concerned because there are unexploded devices around the area from an old military range in Lancelin.
So far, the fire has scorched nine and a half thousand hectares of land.
Temperatures are rising in WA over the next few days and are forecasted to reach above 40 degrees on Friday and Saturday.