When will the new legislation come into effect? The model Work Health and Safety (WHS) Act, model work health and safety regulations, and model codes of practice are anticipated to come into effect on 1 January 2012. What does ‘model’ work health and safety (WHS) legislation mean? ‘Model’ refers to Safe Work Australia’s model WHS framework, which includes an act, regulations and codes of practice, to be adopted by each jurisdiction. Each state and territory will enact their own laws to mirror these model laws.