A fire-blast resistant door assembly comprises a door frame and a door leaf. The front part of the door leaf comprises a front panel and a front stiffener that delimits a cavity from the inside of the front panel, wherein a sheet refractory material is installed in said cavity. The rear part of the door leaf comprises a rear panel and a rear stiffener that delimits a cavity from the inside of the rear panel. A support structure made of metal is installed in said cavity. The front and the rear parts of the door leaf are mutually connected through the layer of the refractory material, forming the thermal break therebetween, so that said support structure abuts against said sheet refractory material. The door frame, in its turn, comprises a front part and a rear part mutually connected through a layer of the refractory material forming a thermal break.