Ship machinery maintenance is a core technical aspect to achieve expected reliability, availability and efficiency in system level. Since maintenance practiceon-board ships is so critical, the integrity of planning, coordination and execution stages are expected to be well functioned. At this insight, this study considers the implementation potential of maintenance 4.0, relatively a new concept defined within industrial 4.0 initiative, in marine engineering field. In detail, the generic design and implementation requirements of maintenance 4.0 including key opportunities and challenges are identified. Moreover, a comprehensive requirement analysis is conducted to adopt maintenance 4.0 concept into ship machinery systems of existing and newbuilding merchant ships.