The constitutional division of powers - legislative, executive, judicial - is a useful concept. It is not perfect. The executive government has delegated legislative powers - that is, the power to make regulations and other statutory instruments. Parliaments, correspondingly, have executive functions. These are more than just the function of running themselves, for example managing court libraries. They have, or should have, capacity to manage legislative schemes:
Parliamentary oversight over the implementation of Acts;
review and disallowance of regulations;
oversight of other legislative instruments such as guidelines and codes.