A coroner has condemned Corrections over the death of a Christchurch prisoner

25-year-old Kodi Bennett died from self-inflicted injuries at Rolleston Prison after being left unobserved in April 2016.

Open Justice reports Coroner Mary-Anne Borrowdale describes some steps taken by staff as 'reckless and irresponsible'.

She reveals Bennett had made an attempt on his life with a 'personal care instrument' while at Christchurch Men's Prison at the beginning of April.

The same object was given to him before his death two weeks later.

She recommends improving the observation of higher risk prisoners -- and the therapeutic environment in at-risk units.