Emergency services were called to Gas Works Lane in Prestatyn at about 23:30 BST on Sunday following reports of the vehicle ablaze. Officers attending the scene found a body inside the van. The identity of the person is unknown.
Detective Superintendent Chris Bell said officers are working at pace to identify the victim. Once the identity is known, specialist trained officers will be assigned to support the family as soon as possible.
A police cordon remains in place as investigations continue. Det Supt Bell acknowledged the incident may cause concern within the local community and said there is a visible policing presence in the area.
North Wales Police have appealed for anyone who was in the Gas Works Lane area of Prestatyn between 22:45 and 23:45 on Sunday, who saw or heard anything unusual, to come forward.