Denis Marshall's best known post was as Minister of Conservation from 1990 to 1996 during which he also acted as Associate Minister of Agriculture and Associate Minister of Employment. He resigned from his role as a minister in May 1996, roughly a year following the April 1995 Cave Creek disaster in which 14 people died. A commission of inquiry found that whilst many individual mistakes contributed to the accident, a root cause was that the Department of Conservation had been under-funded and under-resourced for the role it was expected to achieve, and from the time of its creation in 1987 it had remained disorganised internally with few consistently used project and safety management systems, or formally qualified staff for much of the required work. Intense scrutiny of the Minister followed, as well as scrutiny of the government's funding priorities.
