Out-of-control bushfires in Victoria’s west are now estimated to have reached “the size of Singapore” as more residents are urged to evacuate.

Communities in Bellellen, Pomonal and Black Range were told on Friday morning to leave the area immediately.

Relief centres have been established in Ararat at the Alexander Community Oval and at Grampians Community Health in Stawell.

Those in Barton, Jimmy Creek, Kia Ora, Londonderry, Mafeking, Moyston, Watgania and Willaura North have been warned it is too late to evacuate and that they must urgently take shelter.

Authorities are advising residents in these areas to protect themselves and their families by wearing long-sleeved shirts and trousers, bringing pets inside, and sheltering in a room with two exits after ensuring all doors, windows or vents, and cooling systems are closed and shut off.

A warning from VicEmergency issued on Friday morning reads: “The extreme heat is likely to kill you well before the flames reach you.”

Emergency services near a bushfire in Grampians National Park in Victoria. Photo / AFP

The ABC reported on Friday morning that representatives of the State Control Centre estimated the blaze – which has grown from 6000ha to 74,000 within a week – was now “somewhere around the size of Singapore”.

Hundreds of homes in Moyston, Willaura and Pomonal have lost power after the fire devastated crucial components of the region’s network.

A spokesperson for Powercor said 363 customers in the region were without electricity.

“We are working with emergency service agencies to safely gain access to the area to allow us to assess the damage and conduct repairs.”

Some telephone communications were also disrupted or cut off after the Mt Williams communications tower was destroyed on Boxing Day.

It comes after more than 600 firefighters – including roughly 100 back-up personnel from interstate – sacrificed their Christmas to protect homes in the region.