Reward for info on Perth arsonist

Two bushfires that threatened lives and homes in Ellenbrook in Perth's north are believed to have been deliberately lit.

Arson detectives are urging anyone who saw something suspicious on Monday about 3.50pm on Banrock Drive and about 4.40pm on Helms Loop to report it to police.

Rewards of up to $50,000 are available for information that leads to the identification and conviction of an arsonist.