The Corrections union is sounding the alarm on prison capacity. 

The Ministry of Justice projects the prison population will increase 36 percent by 2035 to more than 14,000 people.

The Corrections Association of New Zealand says facilities are already at 95 percent capacity. 

National President Floyd du Plessis says he predicts it will be completely full within 18 months. 

He says some projects will slightly help - but more serious action needs to be taken now. 

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