fourth child has come forward to police over a monstrous inferno that tore through an empty building in Sydney, while two homeless people known to sleep in the building are still unaccounted for.

Clean-up crews have been able to access the Randall Street site in Surry Hills five days after the blaze, as they prepare the old heritage building for demolition.

A bobcat was brought in today to clear bricks and debris from the surrounding streets, while firefighters were tasked with smashing the windows of an adjacent office after they were damaged by heat.