A Waramanga woman has been charged after allegedly using a blowtorch to deliberately light a series of grass fires in Fisher and Chifley.

Police allege the 27-year-old lit at least four fires on Badimara Street in Fisher and Waldock Street in Chifley about 3.50pm on Wednesday.

A member of the public allegedly saw the woman lighting the fires and tried to stop her before being assaulted. He was treated in hospital for minor injuries.

Two of the larger fires were extinguished by firefighters before police arrested the woman in Chifley.

She has been charged with an act to cause public alarm and common assault.

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