A woman has suffered serious injuries after being set on fire by a stranger, police allege.

The woman was approached by a man on Carmody Place in Bunbury, about two hours south of Perth, just before 4pm on Monday November 2.

Police said the male was unknown to the woman, and allegedly threw a flammable liquid on her before igniting the fluid.

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“The woman sustained serious injuries,” police said.

She was taken to the Fiona Stanley Hospital in Perth for treatment.

The accused, a 40-year-old man from Bunbury, was arrested on Tuesday.

He was charged with one count of grievous bodily harm and remanded in custody ahead of an appearance in Bunbury Magistrates Court on December 3.