A group of rangers found the fire covered in sand but still radiating heat, with surrounding vegetation in close proximity on fire.

The bushfire took hold and subsequently burned approximately 87,000 hectares of the World Heritage site.

On December 21, detectives from Maryborough CIB charged four people in relation to lighting an unauthorised campfire which was not properly extinguished.

A 24-year-old Warwick man has been charged with the unlawful lighting of a fire and leaving a fire unattended.

A 21-year-old Rosenthal Heights man, a 24-year-old Rosenthal Heights man and a 23-year-old Massie man have been charged with one count each of the unlawful lighting of fires.

They will appear in Hervey Bay Magistrates Court on January 21 next year.

A 17-year-old boy will be dealt with under the Youth Justice Act.