A holographic weak-signal enhancement technique (WSET) is described which enhances the image of the source of a weak signal of interest in the presence of an unwanted strong signal with very little a priori knowledge of the latter. The technique is most suitable for imaging applications in fields such as seismic or oceanographic holography, where the desired weak-scattered signal is often overwhelmed by a strong reflected signal from interfaces between different media. The feasibility of the WSET has been shown by simulating a two-solid-layer acoustic problem on a digital computer. Well-defined enhanced images have been obtained for target scattering which is so much weaker than a strong reflected signal that the target images were lost in noise using conventional holographic reconstruction.