Sydney woman charged over fatal house fire

A woman has been charged with murder over the death of Jeffrey Lindsell in a house fire in Sydney's south last year.

Mr Lindsell, 39, was rescued from a granny flat on San Remo Avenue in Gymea in a critical condition with extensive burns on October 7.

His elderly parents, who live in the main house, said at the time they woke to a horrific scene.

"We watched our son run out of his burning granny flat - he was on fire," Kathy Lindsell tearfully told reporters.

"At 7am a doctor was telling us our boy was unlikely to survive."

Mr Lindsell died of his injuries in hospital two days later.

On Thursday, police charged a 46-year-old woman, named by Fairfax Media as Mr Lindsell's ex-girlfriend Amanda Zukowski, with murder.

They allege she tampered with the water supply and deliberately lit the fire in the granny flat knowing Mr Lindsell was asleep inside.

She appeared at Newtown Local Court on Thursday, where she was formally refused bail to reappear at the same court on August 14.