Firefighters are battling a blaze at a Merrylands apartment block, with twenty fire trucks on the scene.
It is understood that the fire broke out just after 11.30am, with it starting at a unit block at Todd Street and Sherwood Road.
It started on the top level and then spread to a neighbouring apartment block.
Residents have been evacuated and there have been no injuries reported.
It is currently 34C in Merrylands, with tops of 36C expected.