We investigate the unsteady hydro magnetic free convection by laminar flow of a Newtonian, viscous, electrically conducting and heat generation/absorbing fluid on a continuously vertical permeable surface in the presence radiation effect, chemical reaction and the mass flux. Numerical results were obtained using an efficient numerical method called: Network simulation method for several parameters, such as Prandtl number, Schmidt number, heat absorption coefficient, magnetic field parameter and permeability parameter. We have shown that a good agreement exists between the present results and those in the literature. Mainly it was found that increases in values of time, chemical reaction parameter, absorption radiation parameter, Schmidt number and permeability parameter were associated with increase in the velocity profile, while increases in heat generation parameter, Schmidt number, Prandtl number, magnetic field parameter and permeability parameter led to a decrease in the velocity profile. The results showed that increased the radiation absorption parameter and dimensionless time, led to a rise in the temperature profile, while increases in heat generation parameter and Prandtl number resulted in a decrease in the temperature distribution. Also, it was observed that increases in chemical reaction parameter led to a decrease in the concentration distribution, while decreases in Schmidt number were associated with increases in the concentration distribution. (C) 2013 Elsevier Ltd. All rights reserved.