Non-Equilibrium Molecular Dynamics (NEMD) simulations are used to assess the relevance of hydrodynamics continuous model to describe slip - flow in confined liquids. Results show that the behaviour of liquids can be described by Stokes equation solved using Navier's slip condition. Slip lengths obtained were significantly larger at the liquid-liquid interface than at the solid-liquid interface. We demonstrated a relation between the slip lengths of the liquids and their respective viscosity.