The non-invasive monitoring and examination of wall paintings in grotto sites, tombs and buildings is particularly important since these paintings are often extremely vulnerable. Traditionally, inspection of wall paintings at high resolution (i.e. sub-millimetre resolution) requires either scaffolding or some heavy and cumbersome mechanical structure to lift a person or camera to the upper parts of a wall or ceiling. We have developed a prototype portable remote imaging multispectral camera that operates at ground level for in situ high-resolution colour and spectral imaging of wall paintings. We present here the latest developments for the instrument and examples of how the instrument can be used for diagnosis of wall paintings.