An oil heater is believed the be the source of a blaze which left four members of a family-of-five with serious burns in Hillside.

Firefighters arrived at the scene about 9.25pm to find the home engulfed in flames.

The family, including three children, escaped their burning house as neighbours rushed to the scene to help.

James, 32, and his son Zayne, 7, remain in hospital in a critical conditon after suffering third-degree burns.

James is now in intensive care with burns across his body and deep cuts to his arms, according to a fundraiser set up for the family.

Zayne is also in intensive care with burns to his face, hands, and feet, where he remains in a critical condition.

James’ partner Rochelle, 30, and their older son Izaiah, nine, suffered third-degree burns but are in a stable condition.

Their youngest child Ava-Leigh was not injured.

The two adults were taken to The Alfred Hospital while the boys were taken to the Royal Children’s Hospital.

A neighbour told 9News that James helped his children escape the burning home by smashing a window and pulling them out to safety one by one.

It took 40 minutes for firefighters to control the blaze.

James’ sister Laressa Turetahi said the family have a “long and painful road to recovery”.

“This young family has lost their home, their belongings, and their sense of safety all in a single night,” Turetahi said.

Fire crews remain on the scene.

It is not being treated as suspicious and it is believed a heater caused the blaze.