Powder metallurgy (PM) involves processes of mechanical milling, pressing, and sintering. The last of these can be done by different methods. One promising such method is hot isostatic pressing (HIP), which improves on conventional powder metallurgy by eliminating pores, thereby achieving full density with enhanced properties. This study seeks to show the effect of HIP on the characteristics of PM processed Mg-based alloys. High energy milled powders of commercially pure magnesium, AZ91 magnesium alloy and zinc were mixed and compacted in rectangular forms and then sintered by HIP, at constant temperature and pressure. After HIP, relative density of up to 97% was achieved. For the AZ magnesium alloys processed at 900 rpm, homogeneous precipitation of the β-Mg17Al12 phase was found, while for the specimens milled at 600 rpm this phase was observed in a lamellar form, with these morphological changes suggesting differences in the hardness of the processed materials.