Registration of multi-modal medical images is an essential pre-processing step, for example, for fusion or image guided-interventions. However, the alignment process is prone to high variability in tissue appearance between modalities, in addition to local intensity variations and artefacts. This work introduces a robust multi-modal registration approach that mitigates the undesirable effect of such variability. Robustness is achieved using Huber's loss function for the data fidelity and regularization terms. We propose a novel approach using Huber's criterion, which enables a jointly convex estimation of the motions and the associated scale parameters. We formulate the problem as a complex 2D transformation estimation and investigate a robust total-variation smoothing, as well as a dictionary learning-based data fidelity term. Experiments are conducted using two datasets of multi-contrast MR brain images.