The resident – a 45-year-old man – is recovering in hospital after being assaulted during the invasion.
He was inside his granny flat on Ringrose Avenue, Greystanes, at about 11pm last night when three men allegedly broke in, assaulted him and set the flat alight.
He suffered cuts, bruising and abrasions.
He was treated at the scene by paramedics before being taken to Westmead Hospital in a stable condition.
The flat was not badly damaged.
A crime scene has been established at the home and investigations are underway. The men believed to be responsible for the break in have yet to be found.