The new generation of radio telescopes, such as the Square Kilometre Array, will reach enough sensitivity to provide a density of detected galaxies comparable to that found at optical wavelengths, allowing weak lensing measurements in the radio band. Standard techniques for the measurement of cosmic shear are based on the best fitting of galaxy shapes from images, as they have been developed for optical surveys. However, radio instrumentsmeasure visibilities, i.e. the Fourier transform of the sky image at a finite number of points.Therefore the natural approach to adopt with radio data is working directly in the visibility domain, avoiding systematics due to the imaging process and where the noise is Gaussian. I will present the challenges and the current work for the development of such methods adopting a Bayesian approach.