The Opportunities Party is concerned with what appears to be the overuse of solitary confinment in New Zealand. There are some legitimate uses of solitary confinement, but there are few, and the evidence is that in New Zealand solitary confinment is greatly overused.

Doctor Sharon Shalev’s 2017 report, Thinking Outside The Box, was commissioned by the Human Rights Commission and carried out with UN funding. It looked at how seclusion is used in prisons, health and disability units, a youth justice residence, a children's care unit and police cells. Shalev found that overall, there is a high use of seclusion and restraint in New Zealand and an overrepresentation of ethnic minority groups, in particular Mäori, in seclusion and in prison segregation units. In prisons, women were also much more likely than men to be segregated, and for longer periods. New Zealand segregated prisoners over four times more often than England and Wales. This is especially concerning since that the use of segregation in England and Wales has itself been found to be high.