Corrections is trying to prevent prisoners from stockpiling fruit after inmates were found to have made an alcoholic drink out of it before a major riot at Spring Hill Prison.
The alcoholic concoction also contained hand sanitiser, which has now been removed from all New Zealand prisons.
Corrections chief executive Ray Smith told Parliament this morning that gang-related offenders had been consuming an alcoholic substance for a long period before the eight-hour riot, the worst in a New Zealand prison in 15 years.
The substance was believed to have been made out of an alcoholic hand sanitiser and fermented fruit.
The violent melee involved 23 prisoners and led to a huge fire at the Waikato facility.