Firefighters tackle Karratha bushfire

The alert level for a bushfire that was threatening lives and homes in Western Australia's Pilbara region has been downgraded.

A watch and act alert was issued for people in Walcott Drive and the adjacent streets of Wickham in Karratha on Monday night when the blaze was burning in bushland west of the Hamersley Iron railway line.

Four hours later, the Department of Fire and Emergency Services downgraded the alert to an advice but said the blaze remained out of control and unpredictable.

There is no threat to lives or homes but there is a lot of smoke in the area.

Although there is no immediate danger, people in the area need to remain vigilant in case the situation changes.

The fire started between Boat Beach Road and Walcott Drive and continues to be tackled by firefighters.

Authorities regard the blaze as suspicious.