At least two people have been killed and another is missing as bushfires continue to burn out of control in western Australia, officials say.

Police say the bodies of two men in their 70s have been discovered in the debris of burnt-out houses in the town of Yarloop, south of Perth, BBC reported.

An emergency bushfire warning remains in place for Yarloop.

Emergency services have warned that the towns of Harvey, Cookernup and Wokalup are also facing a big threat.

West Australia Premier Colin Barnett has declared the main area of the fire to be the scene of a natural disaster and eligible for emergency funds.

Residents and holiday-makers in the area - a major beef and dairy farming area - have been evacuated.